ARL-TR-8006 ● Apr 2017

US Army Research Laboratory

Quasi-Static and Dynamic Characterization of 

Equal Channel Angular Extrusion (ECAE) –

Processed and Rolled AZ31 Magnesium Alloy 

Sheet

by Laszlo J Kecskes, Vincent H Hammond, Michael Eichhorst, 

Lothar Meyer, and Norman Herzig

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ARL-TR-8006 ● Apr 2017

US Army Research Laboratory

Quasi-Static and Dynamic Characterization of 

Equal Channel Angular Extrusion (ECAE) –

Processed and Rolled AZ31 Magnesium Alloy 

Sheet

by Laszlo J Kecskes and Vincent H Hammond 

Weapons and Materials Research Directorate, ARL 

Michael Eichhorst, Lothar Meyer, and Norman Herzig

Nordmetall GmbH, Adorf-Neukirchen, Germany

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1. REPORT DATE (DD-MM-YYYY)

April 2017

2. REPORT TYPE

Technical Report

3. DATES COVERED (From - To)

April 2015–January 2016

4. TITLE AND SUBTITLE

Quasi-Static and Dynamic Characterization of Equal Channel Angular 

Extrusion (ECAE) – Processed and Rolled AZ31 Magnesium Alloy Sheet

5a. CONTRACT NUMBER

W911NF-14-1-0517

5b. GRANT NUMBER

5c. PROGRAM ELEMENT NUMBER

6. AUTHOR(S)

Laszlo J Kecskes, Vincent H Hammond, Michael Eichhorst, Lothar Meyer, and 

Norman Herzig

5d. PROJECT NUMBER

5e. TASK NUMBER

5f. WORK UNIT NUMBER

7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES)

US Army Research Laboratory

ATTN: RDRL-WMM-F

Aberdeen Proving Ground, MD 21005-5069

8. PERFORMING ORGANIZATION REPORT NUMBER

ARL-TR-8006

9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR'S ACRONYM(S)

11. SPONSOR/MONITOR'S REPORT NUMBER(S)

12. DISTRIBUTION/AVAILABILITY STATEMENT

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13. SUPPLEMENTARY NOTES

14. ABSTRACT

Previously, we developed a rolling schedule for Equal Channel Angular Extruded (ECAE) AZ31 magnesium (Mg) alloy plate 

material. Herein, we compare the room temperature quasi-static and dynamic mechanical properties of the as-ECAE processed 

plates (with textures A and C) to the subsequently rolled sheet material. Further, our investigation compares the batch-to-batch 

variation of 2 different lots of texture C plate material. Earlier results have shown that the plate material (especially texture A) 

exhibits anisotropic mechanical properties in the transverse and longitudinal directions. While to a large extent the initial ECAE 

process-induced banded microstructure is preserved after rolling, the property difference between the 2 directions is minimized. 

Closer examination of the sheet materials reveals a highly aligned microstructure along the rolling direction, consisting of fine 

sub-10-μm-sized Mg grains. Under dynamic loading conditions, both texture type sheet materials exhibit higher strengths, but 

lower ductility than at quasi-static testing conditions. The texture A sample was more ductile at the higher rates and yielded 

more consistent results than those obtained from the texture C sample.

15. SUBJECT TERMS

Mg, magnesium, ECAE, mechanical properties, equal channel angular extrusion, quasi-static, dynamic characterization 

16. SECURITY CLASSIFICATION OF:

17. LIMITATION

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 ABSTRACT

UU

18. NUMBER

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 PAGES

58

19a. NAME OF RESPONSIBLE PERSON

Laszlo J Kecskes

a. REPORT

Unclassified

b. ABSTRACT

Unclassified

c. THIS PAGE

Unclassified

19b. TELEPHONE NUMBER (Include area code)

410-306-0811

Standard Form 298 (Rev. 8/98)

Prescribed by ANSI Std. Z39.18
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iii

Contents

List of Figures v

List of Tables vii

Acknowledgments viii

1. Introduction 1

2. Experimental Procedures 4

2.1 Extrusion Procedures 4

2.2 Metallographic Sample Preparation 4

2.3 Hot Rolling Procedures 5

2.4 Quasi-Static Tensile Tests 8

2.5 Dynamic Tensile Tests 9

3. Results and Discussion 11

3.1 Microstructural Examination of the As-Received ECAE Plate 

Material 11

3.2 Hot Rolling of the Plates 13

3.3 Microstructural Examination of the Rolled Sheets 18

3.4 Comparison of Unprocessed and ECAE-Processed Sheet Materials 

(Batch 1, per ARL-TR-7644)1 19

3.5 Quasi-Static Tensile Tests of the Recent Batch 2 of ECAE-Processed 

Material 22

3.6 Dynamic Tensile Properties of Rolled Mg Sheets 25

3.7 Influence of Strain Rate on the Mechanical Properties of As-Rolled 

Sheets A26 and C25 28

3.8 Fracture Surface Observations of Failed Samples from the As-Failed 

C25 Sheet 31

4. Conclusions 32
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5. References 34

Appendix. Auxiliary Mechanical Property Data for the AZ31 Magnesium 

(Mg) Alloy Materials 35

List of Symbols, Abbreviations, and Acronyms 47

Distribution List 48
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v

List of Figures

Fig. 1 Macro-photography of the as-received ECAE-processed Mg plate 

material ................................................................................................. 3

Fig. 2 Relationship between the tooling plate and the ECAE plate 

orientations............................................................................................ 4

Fig. 3 Illustration of the micro-section positions of the as-received plates..... 5

Fig. 4 Photograph of the rolling mill (Hugo Sack GmbH).............................. 6

Fig. 5 Photograph of the convection air furnace ............................................. 6

Fig. 6 Tensile specimen geometry and dimensions in mm (as-received ECAE 

material)................................................................................................ 8

Fig. 7 Universal testing machine (schematic)................................................. 9

Fig. 8 Tensile specimen geometry (dimensions in mm) ................................. 9

Fig. 9 A schematic representation of Nordmetall’s rotating wheel machine 10

Fig. 10 Detailed schematic of the rotating wheel machine illustrating the 

various stages of operation: claw release, claw extension, contact and 

engagement of the specimen, and retraction....................................... 11

Fig. 11 Micro-sections of the as-received ECAE Plate 61 (texture C) ........... 12

Fig. 12 Macro-photograph of the 6 rolled sheets; from top to the bottom of the 

photograph the sheets are placed sequentially from 61, 62, 63, 65, 66, 

and 67 (texture C, rolling T = 275 °C, 18 rolling passes, final 

thickness, t = 1.5 mm)......................................................................... 14

Fig. 13 Enlarged view of the edge cracks for sheet 61; typically, damage was 

limited with crack lengths of about 5 to 15 mm ................................. 15

Fig. 14 Enlarged view of the edge cracks for sheet 62; typically, damage was 

limited with crack lengths of about 5 to 15 mm ................................. 15

Fig. 15 Enlarged view of the edge cracks for sheet 63; typically, damage was 

limited with crack lengths of about 5 to 25 mm ................................. 16

Fig. 16 Enlarged view of the edge cracks for sheet 65; typically, damage was 

limited with crack lengths of about 5 to 25 mm ................................. 16

Fig. 17 Enlarged view of the edge cracks for sheet 66; typically, damage was 

limited with crack lengths of about 10 to 25 mm ............................... 17

Fig. 18 Enlarged view of the edge cracks for sheet 67; typically, damage was 

limited with crack lengths of about 10 to 25 mm ............................... 17

Fig. 19 Micro-sections of as-rolled Plate 62 (texture C, t = 1.5 mm)............. 18

Fig. 20 Quasi-static tensile properties of conventional and ECAE-processed 

AZ31 sheet material in the longitudinal direction .............................. 19

Fig. 21 Quasi-static tensile properties of conventional and ECAE-processed 

AZ31 sheet material in the transverse direction ................................. 20
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vi

Fig. 22 Engineering stress–engineering strain diagram for ECAE processed 

Plate 61................................................................................................ 23

Fig. 23 Comparison of the 1% flow stress and UTS from the 2 batches of 

ECAE processed plates....................................................................... 24

Fig. 24 Comparison of elongation to fracture and reduction of area from the 2 

batches of ECAE processed plates...................................................... 24

Fig. 25 Macro-photographs of the A26 and C25 sheets, respectively ............ 26

Fig. 26 Engineering stress–engineering strain diagram for samples from the 

A26 sheet, tested under dynamic tensile loading conditions.............. 27

Fig. 27 Engineering stress–engineering strain diagram for samples from the 

C25 sheet, tested under dynamic tensile loading conditions.............. 27

Fig. 28 A comparison of the 1% engineering flow stress obtained from quasistatic and dynamic tensile tests for the A26 and C25 sheets .............. 29

Fig. 29 A comparison of the UTS obtained from quasi-static and dynamic 

tensile tests for the A26 and C25 sheets ............................................. 30

Fig. 30 A comparison of the elongation to failure obtained from quasi-static 

and dynamic tensile tests for the A26 and C25 sheets........................ 31

Fig. 31 Fracture patterns of 2 parallel specimens of the C25 sheet. Note the 

gage width of the specimens is 3 mm. ................................................ 32

Fig. A-1 Load–displacement curve for equal channel angular extrusion (ECAE) 

processed Plate 61............................................................................... 36

Fig. A-2 Load–displacement curve for ECAE processed Plate 62 ................... 37

Fig. A-3 Load–displacement curve for ECAE processed Plate 63 ................... 38

Fig. A-4 Load–displacement curve for ECAE processed Plate 65 ................... 39

Fig. A-5 Load–displacement curve for ECAE processed Plate 66 ................... 40

Fig. A-6 Load–displacement curve for ECAE processed Plate 67 ................... 41

Fig. A-7 Quasi-static engineering stress–engineering strain diagram for Plate 

3.1 (as received, no ECAE); 8 rolling passes...................................... 42

Fig. A-8 Quasi-static engineering stress–engineering strain diagram for Plate 

3.2 (as received, no ECAE); 8 rolling passes...................................... 43

Fig. A-9 Quasi-static engineering stress–engineering strain diagram for ECAE 

processed Plate 26, rolled into sheet A26; texture A; 14 rolling passes

............................................................................................................. 44

Fig. A-10 Quasi-static engineering stress–engineering strain diagram for the 

ECAE processed Plate 25, rolled into sheet C25; texture C; 14 rolling 

passes .................................................................................................. 45

Fig. A-11 Quasi-static engineering stress–engineering strain diagram for ECAE 

processed plate 13; texture C.............................................................. 46
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vii

List of Tables

Table 1 Overview of the new as-received ECAE-processed plates (all 

texture C) .............................................................................................. 2

Table 2 Overview of the rolling passes.............................................................. 7

Table 3 Quasi-static tensile test results for AZ31 rolled sheet types with and 

without prior ECAE processing.......................................................... 21

Table 4 Quasi-static tensile test results for AZ31 plates after ECAE 

processing ........................................................................................... 25

Table 5 Mechanical properties of the A26 and C25 sheets under dynamic 

tensile loading ..................................................................................... 28
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viii

Acknowledgments

Special kudos to Messrs. Gallaher and Runk for performing the equal channel 

angular extrusion processing of the AZ31B magnesium alloy plates and for the 

macrophotography of the plate and rolled sheet materials.
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1

1. Introduction

Magnesium (Mg) and its alloys, with their low-mass densities, may offer new 

opportunities in many structural applications. For this reason, the US Army 

Research Laboratory (ARL) conducted a 5-year research program that developed 

high-strength Mg alloys through severe deformation processing methods. Although 

test results indicated that it is unlikely that Mg alloys will directly replace steel or 

aluminum as a monolithic armor material, it could be potentially used as a 

component in composite structures. With a density of about a quarter of steel, Mg 

may find a unique and/or niche utilization in applications such as personnel body 

armor where the reduction of mass and any type of weight savings is paramount, 

provided the ultrahigh-strength plates could be formed into thin sheets. 

Because of its low melting point and good castability, many components made from 

Mg can be produced by casting. Unfortunately, such cast parts have poor 

mechanical properties, for example, low strength and ductility, and, therefore, 

cannot be used for many structural applications. Moreover, wrought Mg sheets or 

plates are very difficult to produce because of the intrinsically low room 

temperature ductility resulting from Mg’s low-symmetry hexagonal close-packed 

crystal structure (basal slip only). However, the ductility of Mg can be increased 

significantly by increasing the processing temperature to approximately 300 °C. 

Unfortunately, despite the availability of alternative deformation mechanisms 

(prismatic and pyramidal slip and twinning), at or above this temperature, dynamic 

recrystallization processes take place that could negate the benefits of cold and 

warm working.

Previously, in ARL-TR-7644,1 April 2016, we have reported good success with 

large-scale warm rolling of AZ31B Mg alloy plate material (15.24 × 15.24 × 1.27 

cm) subjected to equal channel angular extrusion (ECAE). In that report, we 

described a possible sequence of rolling steps for reducing the initial plate thickness 

from about 9 to 1.5 mm without the introduction of significant grain growth or edge 

cracking in the rolled sheet material. It was determined that a rolling temperature 

of about 275 °C, with a degree of deformation of about 10% per rolling pass and a 

rolling speed of about 1 m/s was very promising. Moreover, the results indicated 

the importance of starting texture, as one set of the ECAE-processed plates proved 

less susceptible to edge cracking and thus yielded a more crack-free sheet product.

During extrusion, the ECAE plates were wrapped in a thin layer of Teflon sheathing 

to reduce frictional forces. However, the sheathing wrinkled, crinkled, flaked, or 

folded, causing the formation of a large number of surface and bulk defects in the 

Mg plate material. Although the affected layer was removed by surface milling 
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2

prior to the rolling experiments, it rendered the initial plates somewhat thinner than 

their nominal dimension of 12.7 mm. Since then, the use of Teflon was reevaluated 

and its attachment modified, which resulted in an overall improvement of the 

extrusion procedures. In turn, this also reduced the number of surface defects. As a 

result, the decision was made to demonstrate the applicability and reproducibility 

of this previously developed method with additional ECAE-processed plates with 

a starting thickness of 12.5 mm. 

Additionally, before the onset of these second set of rolling experiments, the 

mechanical properties of one representative ECAE plate from this batch was 

measured and compared to the texture C plate results from the previous 

investigation. Furthermore, the tensile properties of 2 representative plates (namely 

A26 and C25) from each texture type, A and C, were measured at higher dynamic 

rates using a unique rotating wheel testing apparatus. This equipment, developed at 

Nordmetall, is capable of applying a tensile load at a rate of about 150 s–1

. These 

results were compared to those of the mechanical properties under quasi-static 

loading. As such, the influence of strain rate on the strength and ductility could be 

determined.

For extending the scope of the rolling experiments, the 6 new ECAE processed 

plates with a thickness of about 12.5 mm were shipped from ARL, Aberdeen 

Proving Ground, Maryland, to Nordmetall GmbH, Adorf-Neukirchen, Germany 

(Table 1). Macrophotography of the as-received plates are shown in Fig. 1. Even 

though the defects were reduced in number and size, cracks and surface 

imperfections, especially at the edges, can be still observed. The load versus 

displacement curves obtained during ECAE processing for each of the plates is 

presented in the Appendix. These curves are very useful in identifying any type of 

premature or nonuniform deformation (e.g., shear localization and failure) in the 

extruded material.

Table 1 Overview of the new as-received ECAE-processed plates (all texture C)

Description Thickness

(mm)

Width

(mm)

Length

(mm)

Plate 61 ~12.5 ~153 ~128

Plate 62 ~12.5 ~153 ~128

Plate 63 ~12.5 ~153 ~128

Plate 65 ~12.5 ~153 ~128

Plate 66 ~12.5 ~153 ~128

Plate 67 ~12.5 ~153 ~128
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Fig. 1 Macrophotography of the as-received ECAE-processed Mg plate material
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2. Experimental Procedures

2.1 Extrusion Procedures

To develop the appropriate post-ECAE C texture type in the plates, similar 

procedures as those used in the previous trials were adopted in this study.

l

Briefly, 

these entailed sectioning the 15.24- × 15.24- × 1.27-cm (6- × 6-

× 0.5-inch) plates from a large block of AZ31B tooling plate material, then 

extruding each plate for a total of 6 passes, consisting of 2 A passes at 225 °C; 2 C 

passes at 200 °C; and 2 C passes at 150 °C. For route A there is no rotation of the 

plate between passes; for route C, the plate is rotated by 180° around the plate 

normal before the next pass. An exception to the previously used procedures was 

that Plates 61–67 were sectioned in a different orientation from the tooling plate 

(Fig. 2). Previously, the orientation of the plate normal in the extruded and tooling 

plates was parallel. As such, during the subsequent ECAE processing, the 

extrusions essentially took place in the rolling direction. In the current extrusions, 

the orientation of the extruded plate normal was perpendicular to that of the tooling 

plate. That is, the extrusion took place in the transverse direction. This orientation 

was more favorable for producing crack-free plate material on the first pass. 

Fig. 2 Relationship between the tooling plate and the ECAE plate orientations

2.2 Metallographic Sample Preparation

The microstructure of the ECAE processed AZ31 material was investigated in the 

as ECAE and as-rolled condition. Representative specimens were taken from the 

transverse and longitudinal directions of Plate 61 (Fig. 3). The specimens were 
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mounted in an epoxy resin and prepared using conventional metallographic 

techniques. A final etching, using diluted picric acid, was used to better reveal the 

underlying grain structure. 

Fig. 3 Microsection positions of the as-received plates

2.3 Hot Rolling Procedures

The rolling experiments were performed in cooperation with the Technical 

University Bergakademie Freiberg, a leading university in Germany for the 

production of Mg sheet materials. After preheating, the initially 12.5-mm-thick 

plates were rolled to a thickness of about 1.5 mm. The hot rolling was performed 

on a dual rolling mill (Hugo Sack Mills, formerly of Dusseldorf, Germany) 

(Fig. 4). The diameter of the roller was about 360 mm, with a maximum rolling 

force of 2400 kN. The rollers are driven by a 160-kW electric motor capable of 

producing a torque of 30 kN·m. The rollers were preheated to about 120 °C with 

electric blankets before the rolling experiments, and a lubricant was sprayed on the 

rollers before each rolling pass. The rolling speed was about 1 m/s, a common 

rolling speed for AZ31. 
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Fig. 4 Rolling mill (Hugo Sack GmbH)

The preheating (about 30 min at 275 °C) and intermediate annealing between the 

rolling steps (about 15 to 20 min at 275 °C) was performed in a convection air 

furnace (Fig. 5). A homogenization annealing treatment was not performed before 

the start of the rolling experiments.

Fig. 5 Convection air furnace
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The rolling experiments started with preheating the plates at about 275 °C for about 

30 min in the convection air furnace followed by 18 rolling passes and 17 

intermediate annealing treatment steps (Table 2). As the table illustrates, the degree 

of deformation for every rolling pass was about 10% for the first 15 rolling passes. 

Because of the previously positive experience with increasing the extent of 

deformation for the last rolling passes, the degree of deformation for the last 3 steps 

was increased to about 20%. Compared with the procedures described in ARL-TR7644,1 more rolling passes were necessary in these experiments. This was a direct 

consequence of the greater initial thickness of the as-received plate material. To 

prevent and minimize further crack growth, after every rolling pass an intermediate 

annealing at a temperature of 275 °C for 15 to 20 min was performed. 

Table 2 Overview of the rolling passes
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2.4 Quasi-Static Tensile Tests

The mechanical properties of the as-received plates were determined using quasistatic tensile tests at room temperature and strain rates of about 10–3 s–1

. Small 

sections of Plate 61 were cut off for fabricating the tensile specimens in both the 

longitudinal and transverse directions relative to the extrusion direction. The tensile 

specimen geometry and pertinent dimensions are shown in Fig. 6. The gage length 

was about 10.5 mm.

Fig. 6 Tensile specimen geometry and dimensions in millimeters (as-received ECAE 

material)

The tensile tests were performed using a universal testing machine (Zwick/Roell 

Company GmbH, Ulm, Germany). The maximum force of the testing machine is 

100 kN and the testing velocity can be varied between 0 mm/min and 500 mm/min. 

The experimental setup, including the load frame, is shown schematically in Fig. 7. 

The testing load frame consists of a stiff frame, 2 ball bearing screw spindles, and 

a crosshead connected with the ball bearing screw spindles. The forces were 

measured with a load cell with a maximum force of 5 kN. The specimen elongation 

was measured with a fine displacement extensometer.
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Fig. 7 Universal testing machine (schematic)

2.5 Dynamic Tensile Tests

The mechanical properties of the as-rolled ECAE processed material was 

investigated by dynamic tensile tests at room temperature and strain rates of about 

150 s–1. The tensile specimen geometry is shown in Fig. 8. The gage length is about 

9 mm and the test specimen width about 3 mm. The specimen thickness was about 

1.5 to 1.65 mm. Again, representative specimens were taken along the longitudinal 

and transverse directions relative to the rolling direction. 

Fig. 8 Tensile specimen geometry (dimensions in millimeters)

The tensile tests at high strain rates of about 150 s–1 were performed using a rotating 

wheel machine. The rotating wheel machine, Figs. 9 and 10, is employed for tensile 

test velocities from 1 m/s up to about 40 m/s. It consists of a test frame stand, motor, 

and a large flywheel (220 kg) with a retractable claw. Figure 10 shows the claw 
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unlocked, then released at the required rotational test velocity and, after its release, 

it contacts the yoke (or bottom) of a stationary sample holder. As the extended claw 

contacts and engages this yoke, it pulls on the test specimen, which is held in the 

holder. The force measurement is obtained from strain gages attached to the 

specimen. Assuming that the Young’s modulus is independent of the strain rate, the 

stress can be calculated from the strain gage signals and the cross sectional area of 

the specimen. 

Fig. 9 Nordmetall’s rotating wheel machine (schematic)
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Fig. 10 Rotating wheel machine illustrating the various stages of operation: claw release, 

claw extension, contact and engagement of the specimen, and retraction

Because of the high-rotational energy capacity of this apparatus compared to the 

energy consumed during the impact, it is reasonable to assume that the test velocity 

is nearly constant up to the failure of the sample, even for materials with high 

strength and high ductility. As such, to determine precise yield stress values, the 

strain gages were attached to the gage length to measure the elastic deformation 

strains as well as a part of the plastic deformation up to about 2% or 3%. For larger 

plastic deformations, the strain measurements were carried out using an electrooptical extensometer with a bandwidth of 400 kHz.

3. Results and Discussion

3.1 Microstructural Examination of the As-Received ECAE Plate 

Material

Microsections in the longitudinal and transverse directions of Plate 61 were 

prepared from the as-received ECAE material. Figure 11 shows typical 

microsections of the inner and outer zones. The appearance of these sections are 

very similar to those of the initially processed texture C plates.

1 The difference in 

initial plate orientations did not have a significant effect on the microstructure 
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evolution. Further, if the inner and outer zones of the plate are compared to each 

other, the microstructures are found to be very similar. The bulk of the ECAE 

material exhibits a very fine microstructure that could not be thoroughly 

investigated by optical microscopy alone. In addition to the clearly visible 

macroscale features such as the deformation bands, some of the finer scale 

microstructure is not easily discernible at these magnifications. However, the 

optical images are of sufficiently good quality to distinguish between the regions 

of smaller and larger grains with a diameter of about 50 μm. This is especially 

prominent in the longitudinal microsections; the series of shear bands with an angle 

of about 45° relative to the ECAE extrusion processing direction can be observed. 

There is extensive deformation in these regions. It is reasonable to attribute this 

shearing and the appearance of these shear bands to the nature of the ECAE 

processing route and active deformation mechanisms at the step-down extrusion 

temperatures. In the transverse microsections, there is extensive deformation but 

without the 45° tilt relative to the extrusion direction. Furthermore, small and large 

precipitate structures were observed in all microsections. While necessary to fully 

describe the as-extruded microstructure, the more detailed examination of these 

structures by scanning electron microscopy (SEM) and energy dispersive X-ray 

analysis will be deferred to a subsequent study.

Fig. 11 Microsections of the as-received ECAE Plate 61 (texture C)
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3.2 Hot Rolling of the Plates

In general, the surface quality of the plates produced for this study was considerably 

better than those of the previously supplied plates.

1 However, the plates were still 

characterized by small edge cracks transverse to the extrusion direction on the 

underside of the plates (see Fig. 1). 

The rolling experiments started with a preheating the plates to 275 °C for about 

30 min in the convection air furnace followed by 18 rolling passes and 17 

intermediate annealing steps for about 15 to 20 min at 275 °C (see Table 2 for the 

rolling schedule). Good rolling results were obtained when 18 rolling passes were 

used to attain a thickness of about 1.5 mm. Only small edge cracks could be 

observed for all of the rolled sheets (see Fig. 12). The reason for these cracks could 

be traced to extrusion-induced defects in the as-received original plate material. 

These small transverse cracks remained in each of the sheets after each rolling pass, 

however, without significant growth. As such, the crack lengths at the edges of the 

final as-rolled sheets varied between 5 and 25 mm, leaving a crack-free width of 

about 120 to 130 mm. Figures 13–18 show that the extent of the damaged region 

varied from sheet to sheet.
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Fig. 12 Macrophotograph of the 6 rolled sheets; from top to the bottom of the photograph 

the sheets are placed sequentially from 61, 62, 63, 65, 66, and 67 (texture C, rolling T =

275 °C, 18 rolling passes, final thickness, t = 1.5 mm)
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Fig. 13 Enlarged view of the edge cracks for sheet 61; typically, damage was limited with 

crack lengths of about 5 to 15 mm

Fig. 14 Enlarged view of the edge cracks for sheet 62; typically, damage was limited with 

crack lengths of about 5 to 15 mm
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Fig. 15 Enlarged view of the edge cracks for sheet 63; typically, damage was limited with 

crack lengths of about 5 to 25 mm

Fig. 16 Enlarged view of the edge cracks for sheet 65; typically, damage was limited with 

crack lengths of about 5 to 25 mm
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Fig. 17 Enlarged view of the edge cracks for sheet 66; typically, damage was limited with 

crack lengths of about 10 to 25 mm

Fig. 18 Enlarged view of the edge cracks for sheet 67; typically, damage was limited with 

crack lengths of about 10 to 25 mm
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3.3 Microstructural Examination of the Rolled Sheets

After rolling to a thickness of about 1.5 mm, the microstructure of the sheet 

materials was investigated at their respective inner and outer regions. As was done 

for the as-received plate material, representative microsections were taken in both 

the longitudinal and transverse orientations.

After rolling, larger areas, with a much higher degree of deformation, are observed 

for all sheets. The microstructure is highly heterogeneous, with alternating coarseand fine-grained regions. This heterogeneity likely carried through from the ECAE 

process. However, the more refined microstructure containing very fine grains 

(Fig. 19) is likely determined by further recrystallization processes that occurred 

during rolling. Also, note the more prominent alignment of the precipitate colonies 

and substructures in the rolling plane (longitudinal) direction between the zones of 

small and large deformation. Occasionally, larger grains with about a 10-μm grain 

size are found. In the regions with larger grains, small twins are observed, which 

were formed due to the relatively low rolling temperature and high-deformation 

degree.

Fig. 19 Microsections of as-rolled Plate 62 (texture C, t = 1.5 mm)
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3.4 Comparison of Unprocessed and ECAE-Processed Sheet 

Materials (Batch 1, per ARL-TR-7644)1

In Figs. 20 and 21, bar graphs summarizing the longitudinal and transverse quasistatic tensile properties of rolled AZ31 sheets obtained from a conventional supplier 

and the ECAE material produced for this study are compared. The properties of the 

rolled sheet 3.2 (without prior ECAE processing), which was evaluated previously 

and reported in ARL-TR-7644,1 were included for comparison with the properties 

of the ECAE processed sheets of A26 and C25. Sheet 3.2 was rolled at 425 °C, for 

a total of 8 rolling passes to a thickness of less than 1.5 mm. An equivalent sheet, 

3.1, was subjected to a final anneal treatment at 330 °C for 30 min; this annealing 

step caused a roughly 10% decrease in strength, but a concurrent increase in 

ductility. The former temperature is considerably higher than the recent minimum 

of 275 °C obtained through optimization of the rolling conditions described herein. 

Unlike the specimen geometry shown in Fig. 6, all of these tensile property 

investigations were performed using a slightly different flat specimen geometry 

(l0 = 15 mm, w = 5 mm, and t = 1.5–1.65 mm). The stress-strain tests were 

conducted at a nominal strain rate of 10-3 s-1 and at room temperature. The stressstrain diagrams for sheets 3.1, 3.2, A26, and C25 are provided in the Appendix.

Fig. 20 Quasi-static tensile properties of conventional and ECAE-processed AZ31 sheet 

material in the longitudinal direction
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Fig. 21 Quasi-static tensile properties of conventional and ECAE-processed AZ31 sheet 

material in the transverse direction 

A more detailed review of the prior results indicates that the transverse and 

longitudinal strength levels are about the same for the texture A plate material. 

However, the ductility in the latter direction is lower. In comparison, in the texture 

C plate, the longitudinal strength level is considerably lower, while the ductility in 

the 2 directions is more uniform. After rolling, both texture types have similar final 

strength levels, but during rolling, the preexisting and retained anisotropy (or 

asymmetry) in ductility causes the texture A plate to develop cracking. Thus, the 

more uniform ductility of the texture C plate material allows it to be processed more 

easily. In other words, the rolling process improves the strength of the materials, 

most likely, due to grain size refinement via recrystallization, but without affecting 

the initial ductility. That is, in the texture A plates, the inherent lower ductility in 

the longitudinal direction hinders further processing.

Compared with the conventional AZ31 sheet, the elongation to failure values in the 

rolled texture A and C sheets (A26 and C25, respectively) decrease, indicative of 

the fact that the preferential alignment of the grains and potentially the precipitates 

along the rolling direction may not be necessarily advantageous. However, in the 

transverse direction, this alignment does not affect the benefits gained from the 

increase in the flow stress and ultimate tensile strength.
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Table 3 lists the average values of the 0.5% and 1.% engineering flow stress, 

ultimate tensile stress (UTS), elongation to failure, εf, and reduction of area (i.e., 

necking to failure), q. For the conventional AZ31 sheet 3.2, the stress and strain 

values listed are an average of 2 tests; whereas, for the 2 ECAE processed sheets 

(textures A and C, respectively), the stress and strain values listed are an average 

of 3 tests. 

Table 3 Quasi-static tensile test results for AZ31 rolled sheet types with and without prior 

ECAE processing

Notes: UTS = ultimate tensile stress; εf = elongation to failure; and q = reduction of area (necking to failure); 

RT = room temperature

Examination of the data in the figures and Table 3 indicates that in the longitudinal 

direction there is a slight increase in the strength of the ECAE processed material 

compared to the conventional sheet material. However, the elongation to failure 

decreases for both texture types. If the conventional material with a εf value of 

22.4% is compared with the ECAE processed materials, with εf values of 13.2% for 

A26 and 18.0% for C25, the decrease is quite significant, especially for the texture 

A sheet.

Unlike the similar properties in the longitudinal direction, a comparison of the 

mechanical properties in the transverse direction indicates that there is a fairly large 

increase of about 70 MPa or 30% in the 1% flow stress and a notable increase of 

about 30 MPa or 11% in the UTS for the ECAE processed materials relative to the 

Specimen Temperature Strain Rate 0.5% Engineering 

Flow Stress

1% Engineering 

Flow Stress UTS εf q

[°C] [s-1] [MPa] [MPa] [MPa] [%] [%]

Conventional 

AZ31 Sheet 

(3.2)

RT 10-3 238 245 282 22.4 32.65

ECAE AZ31 

Sheet (A26) RT 10-3 247 258 285 13.2 16.2

ECAE AZ31 

Sheet (C25) RT 10-3 253 262 290 18.0 23.4

Conventional 

AZ31 Sheet 

(3.2)

RT 10-3 210 216 274 22.3 14.85

ECAE AZ31 

Sheet (A26) RT 10-3 277 283 303 21.5 41.8

ECAE AZ31 

Sheet (C25) RT 10-3 284 288 307 21.8 37.0

Quasi-Static Tensile Test Results

Longitudinal

Transverse
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conventional material. Also, the hardening is greater, especially in the conventional 

material. The elongation to failure remains nearly constant at about 22% between 

the various texture types. However, the differences in the necking to failure, 14.9% 

versus 41.8% and 37.0%, respectively, are significant and indicative that the 

conventional Mg alloy is more brittle than either ECAE processed sheet.

As was noted previously, there is a definite positive effect of ECAE processing on 

the mechanical properties; however, these benefits to improvements in ductility can 

be observed in the transverse, but not in the longitudinal direction. In part, this is 

attributed to a strong basal texture that develops during the extrusion sequence,

which seems to be more pronounced in the longitudinal (extrusion) direction with 

increasing shear deformation with each pass using texture A, but not as much with 

texture C. During ECAE processing, using route C, on every second pass the 

sheared material is sheared back to its “unsheared” state. This action likely helps 

returning the microstructure of the grains to a more equiaxed morphology but 

without changing the preferential basal texture. Furthermore, because there is 

minimal shearing in the transverse direction, the effect of route A versus route C is 

not as pronounced. Lastly, these results are only for uniaxial tensile loading of the 

sheet materials. The performance of the different sheet materials should be 

investigated in the through thickness direction or under multiaxial loading 

conditions.

3.5 Quasi-Static Tensile Tests of the Recent Batch 2 of ECAEProcessed Material

The results of the quasi-static tensile tests from a plate recently produced for this 

study by ECAE processing (texture C, Plate 61) are illustrated in Fig. 22. Similar 

to what was observed before in the Batch 1 texture C plates,1 compared with the 

unprocessed plate material, there is a significant increase in strength and good 

ductility in the transverse direction. The strength in the longitudinal direction is 

approximately one-half of that measured for the transverse direction. If the 

microstructures in the 2 orientations of the plate are compared, it is conceivable that 

the relative weakness in the longitudinal direction could be a result of the highly 

heterogeneous striated substructure consisting of alternating layers of refined and 

unrefined grains, partitioned by shear bands. This was also observed for the texture 

C plates from Batch 1. Regardless, the ductility of this plate from Batch 2 is 

considerably better than that obtained from the Batch 1 plates. Additionally, the 

shapes of the stress-strain curves are slightly different. 
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Specifically, for Plate 13, the transverse stress-strain curve is flatter, but the 

maximum strength is slightly higher, but at the expense of a lower ductility.( See 

the stress-strain curve for Plate 13 in the Appendix, Fig. A-11). Aside from the 

somewhat larger ductility, the differences in the longitudinal stress-strain curves 

are minimal between the 2 batches.

Fig. 22 Engineering stress–engineering strain diagram for ECAE processed Plate 61

A direct and quantitative comparison of the mechanical properties can be gleaned 

from the bar graphs shown in Figs. 23 and 24, with the average values from 3 tests 

listed in Table 4. If the 1% engineering flow stress and the UTS of Plate 61 (Batch 

2) are compared to Plate 13 (Batch 1)

1

, nearly similar strength values can be 

observed in the longitudinal direction (Fig. 23). However, in the transverse 

direction, a slightly decreased 1% flow stress and UTS can be observed for Plate 

61. Interestingly, for Plate 61, in both directions, an increased elongation to fracture 

and reduction in area were determined (Fig. 24). However, a fairly large scatter 

exists in these data for the εf and q values in both batches of plate material, as 

indicated by the magnitude of the error bars. Regardless, because of its better 

ductility, it may be expected that the plates from Batch 2 are more easily deformed; 

that is, its rollability will be the same or better than that of Batch 1.
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Fig. 23 Comparison of the 1% flow stress and UTS from the 2 batches of ECAE processed 

plates

Fig. 24 Comparison of elongation to fracture and reduction of area from the 2 batches of 

ECAE processed plates
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Table 4 Quasi-static tensile test results for AZ31 plates after ECAE processing

Notes: UTS = ultimate tensile stress; εf = elongation to failure; and q = reduction of area (necking to failure); 

RT = room temperature

Subsequent to these comparative tests, the plates from Batch 2 were rolled into 

sheets and returned to ARL for further processing and incorporation into the target 

configuration. No further testing was performed on the as-rolled sheets from Batch 

2. However, much like that observed for the previous texture C plates, it was 

expected that upon rolling the sheets would develop a more uniform strength 

profile. That is, the postrolled longitudinal direction strength was expected to 

increase to roughly match that in the transverse direction. However, the elongation 

to failure in the former direction was expected to remain lower than that in the latter 

direction. 

3.6 Dynamic Tensile Properties of Rolled Mg Sheets

As part of the overall experimental program, the mechanical properties under 

dynamic loading conditions were also determined for the 2 texture types. 

Representative samples from each of the 2 texture types, namely from sheets A26 

and C25 (see Fig. 25 for the characteristics of the sheets; note the better appearance 

of the texture C sheet) were taken. Plate A26 was ECAE processed to develop a 

texture A, and Plate C25 was ECAE processed to develop a texture C. These routes 

were described in more detail in ARL-TR-7644.1 Both plates were rolled at a rolling 

temperature of 275 °C, with a degree of deformation of about 10% per rolling pass. 

The final thickness of both sheets was about 1.5 to 1.6 mm and the rolling speed 

was about 1 m/s. 

[°C] [s-1] [MPa] [MPa] [MPa] [%] [%]

RT 10-3 114 124 178 11.6 13.4

RT 10-3 324 336 346 12.8 20.6

RT 10-3 116 128 190 15.5 16.5

RT 10-3 299 307 330 17.7 25.7

Plate 61

Quasi-Static Tensile Test Results

Transverse

Comparison of Plate Batch Properties - Texture C

Transverse

Longitudinal

Longitudinal

Temperature Strain Rate 0.5% Engineering 

Flow Stress

1% Engineering 

Flow Stress UTS εf q

Plate 13
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Fig. 25 Macrophotographs of the A26 and C25 sheets, respectively

The results of the dynamic tensile tests at strain rates of about 150 s–1 are shown in 

Figs. 26 and 27. Both sets of results show increased strength and ductility. More 

specifically, the increase in strength and the significant increase in ductility are

greater in the transverse direction, as can be observed compared with that in the 

longitudinal direction for the A26 sheet. Similar to the A26 sheet, there is an 

increased strength in the transverse direction compared to the longitudinal direction 

for the C25 sheet. Despite attempts to carefully select and extract the dynamic 

tensile specimens from crack-free areas there are significant deviations in the stressstrain behavior from repeated tests for various specimens in the same orientations. 

This is especially the case for the C25 sheet results. These deviations could be 

explained by the presence of microcracks or failure zones induced in the 

microstructure of the material during roll processing. The mechanical properties of 

the A26 and C25 sheets under dynamic tensile loading conditions are summarized 

in Table 5. 

A26, 275 °C, 10 %

 

C25, 275 °C, 10 %

 
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Fig. 26 Engineering stress–engineering strain diagram for samples from the A26 sheet, 

tested under dynamic tensile loading conditions

Fig. 27 Engineering stress–engineering strain diagram for samples from the C25 sheet, 

tested under dynamic tensile loading conditions
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Table 5 Mechanical properties of the A26 and C25 sheets under dynamic tensile loading

Notes: UTS = ultimate tensile stress; εf = elongation to failure; and q = reduction of area (necking to failure); 

RT = room temperature

3.7 Influence of Strain Rate on the Mechanical Properties of AsRolled Sheets A26 and C25

Previously, the quasi-static tensile test were performed using specimens with gage 

lengths of 15 mm and a width of 5 mm (l0/b = 3). Due to the unavailability of 

sufficient sheet material, the dynamic tests were performed with shorter gage 

lengths of 9 mm and a width of 3 mm (l0/b = 3). In spite of the different gage lengths 

and widths, because the aspect ratios were kept the same, the quasi-static and 

dynamic tensile tests could be compared to one another. Furthermore, the 

deviations between both specimen geometries were found to be negligible because 

the material behaved in a brittle manner and an absence of necking was observed.

If the earlier quasi-static results for the A26 and C25 sheets are compared with those 

obtained in the dynamic tensile tests (l0 = 9 mm, b = 3 mm, l0/b = 3), a significant 

increase in strength with increasing strain rate could be observed. Particularly, as 

[°C] [s-1] [MPa] [MPa] [%] [%]

A26-long #1 RT 150 305 325 10.7 18.2

A26-long #2 RT 150 325 345 13.2 20.1

A26-long #3 RT 150 310 330 10.7 18.1

Average Value 313 333 11.5 18.8

C25-long #1 RT 140 320 330 5.2 7.0

C25-long #2 RT 150 320 330 17.7 16.0

C25-long #3 RT 190 285 290 4.9 6.4

Average Value 308 317 9.3 9.8

A26-trans #1 RT 160 350 360 21.5 37.5

A26-trans #2 RT 170 360 380 20.0 33.4

A26-trans #3 RT 160 355 360 21.2 37.4

Average Value 355 367 20.9 36.1

C25-trans #1 RT 200 355 360 7.9 8.1

C25-trans #2 RT 160 375 375 18.9 13.1

C25-trans #3 RT 160 360 360 13.1 9.1

Average Value 363 365 13.3 10.1

q

C25 Sheet

A26 Sheet

C25 Sheet

A26 Sheet

Dynamic Tensile Tests

Longitudinal

Transverse

Specimen Temperature Strain Rate 1% Engineering 

Flow Stress UTS εf
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illustrated by the 1% flow stress and ultimate tensile stress in Figs. 28 and 29, in 

the longitudinal direction, increases of 10%–20%, and in the transverse direction, 

increases up to 25%, respectively, were measured at the higher strain rate. Such 

increases imply that this material in this rolled state is highly strain-rate sensitive.

Fig. 28 A comparison of the 1% engineering flow stress obtained from quasi-static and 

dynamic tensile tests for the A26 and C25 sheets 
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Fig. 29 A comparison of the UTS obtained from quasi-static and dynamic tensile tests for 

the A26 and C25 sheets

Figure 30 shows the influence of strain rate on the elongation to failure for both 

sheet types. Interestingly, a roughly constant elongation to failure was determined 

for sheet A26 with increasing strain rate. However, in contrast, possibly caused by 

a significant variability in measured ductility values for specimens in both 

orientations (indicated by the error bars in the histogram, and already noted in the 

previously displayed stress-strain diagrams, wherein, the spread in the data was 

quite large), a dramatic decrease in ductility with increasing strain rate can be 

observed for sheet C25. Because all of the specimen measurements were conducted 

with good precision and accuracy, it is believed that the most likely reason for this 

variability could only be explained by defects present (e.g., microcracks) in the asrolled texture C material. That is, the lower than expected elongation to failure may 

be introduced during rolling. Specifically, while rolling will tend to realign and 

even out the highly heterogeneous alternating refined and coarse-grained 

microstructure of the post-ECAE plate along the rolling and transverse directions 

resulting in a more uniform strength distribution, it will not homogenize the 

nonuniform grain size distribution into a more uniform sized grain structure. 

Therefore, it is quite possible that regions with finer recrystallized grains will 

remain weaker, causing lower ductility, especially at higher strain rates. 
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Fig. 30 A comparison of the elongation to failure obtained from quasi-static and dynamic 

tensile tests for the A26 and C25 sheets

3.8 Fracture Surface Observations of Failed Samples from the 

As-Failed C25 Sheet

As described in the previous section, significant deviations of the measured 

elongation to failure of dynamic tensile specimens from the rolled C25 sheet 

material were observed. In particular, εf of 5.2% and 17.7% in samples 

RSO_C25_long_1 and RSO_C25_long_2, respectively, were measured. Because 

of this large discrepancy, the fractured failure surfaces were cursorily examined. 

As expected, different fracture patterns can be observed as shown in Fig. 31. The 

surface of specimen RSO_C25_long_2 with the larger εf fails by smooth shearing 

with an angle of about 45°. In contrast, the surface of specimen RSO_C25_long_1 

is not a smooth sheared surface, but instead, contains a step with a likely brittle

cleavage surface coupled with shearing. This may be the result of a different 

operating failure mode. The study of failure modes was beyond the scope of this 

study; however, to fully investigate the cause for the apparent difference in failure 

modes, a more careful SEM analysis of all fracture surfaces in both orientations 

should be performed. 
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Fig. 31 Fracture patterns of 2 parallel specimens of the C25 sheet. Note the gage width of 

the specimens is 3 mm.

4. Conclusions 

The previously developed rolling schedule for ECAE processed AZ31 Mg alloys, 

using a rolling temperature of about 275 °C, with a rolling speed of about 1 m/s,

and a degree of deformation of about 10% per rolling pass for the first 15 passes 

and about 20% for the last 3 passes showed very promising results for a second 

batch of somewhat thicker plates. After 18 passes, the final thickness of the 

resultant sheet material was about 1.5 mm. Only edge cracks with a length of about 

10 to 15 mm could be observed after the final rolling pass. It is likely that the reason 

for these edge cracks is attributable to inherent defects in the as-received ECAE 

processed material.

The mechanical properties of the as-received ECAE-processed material were

investigated by quasi-static tensile tests at room temperature, and the measured 

properties were compared with the results obtained for Batch 1.1 A comparison of 

the results indicates only slight deviations between these 2 batches. Therefore, if 

applied consistently, very similar rolling results should be expected.

The as-received ECAE processed plates having texture C were highly 

heterogeneous, especially in the longitudinal direction. The plates contained zones 

of uniformly deformed regions, oriented at a roughly 45° slant relative to the 

extrusion direction. These zones were separated by more heavily deformed zones 

that appeared like shear bands. However, after rolling, the microstructure was 

aligned in the rolling direction and consisted of a very fine likely recrystallized 
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33

substructure containing some larger grains of about 10 μm. The quasi-static 

mechanical properties of the plates were consistent with the earlier results for Batch 

1, showing higher yield and ultimate strengths in the transverse direction compared 

to the longitudinal direction. This difference was minimized by rolling the plates 

into sheet material. Additionally, the sheets possessed better mechanical properties. 

Under dynamic tensile loading, at an average strain rate of about 150 s–1, the ECAE 

processed and rolled sheets for both texture type materials show improved strength 

levels. For the texture A sheets, the results were more consistent as the elongation 

to failure was almost constant. However, due to significant deviations in the 

elongation to failure values for identical specimens from the texture C sheets, a 

corresponding decrease in ductility with increasing strain rate was observed. Using 

cursory optical microscopy examination of specimens with different elongations to 

failure, different fracture surfaces (ductile shear versus a combination of brittle 

fracture/ductile shear) were observed. The existence of the mixed modes of failure 

could be a result of microcracks present in the as-rolled material. For a more exact 

validation of this hypothesis, further SEM analyses should be performed. 

Regardless, it may be assumed that with a more homogeneous as-received and asrolled material substructure, better ductility of the texture C sheets could be 

achieved.

This study only examined the material behavior under uniaxial tensile loading. To 

fully validate the impact behavior of these Mg sheets in the intended application, 

multiaxial tension or compression tests are recommended.
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5. References

1. Kecskes LJ, Hammond VH, Eichhorst M, Herzig N, Meyer L. Development 

of rolling schedules for equal channel angular extrusion (ECAE)–processed 

AZ31 magnesium alloy sheet. Aberdeen Proving Ground (MD): Army 

Research Laboratory (US); 2016 Apr. Report No.: ARL-TR-7644.
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35

Appendix. Auxiliary Mechanical Property Data for the AZ31 

Magnesium (Mg) Alloy Materials
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A.1 Part 1: Load–Displacement Curves for the Batch 2 ECAE-Processed 

Plates

Fig. A-1 Load–displacement curve for equal channel angular extrusion (ECAE) processed 

Plate 61
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Fig. A-2 Load–displacement curve for ECAE processed Plate 62
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Fig. A-3 Load–displacement curve for ECAE processed Plate 63
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Fig. A-4 Load–displacement curve for ECAE processed Plate 65
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Fig. A-5 Load–displacement curve for ECAE processed Plate 66
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Fig. A-6 Load–displacement curve for ECAE processed Plate 67
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A.2 Part 2: Engineering Stress – Engineering Strain Diagrams for the 

ECAE and non-ECAE AZ31 Mg Plate and Sheet Materials

Fig. A-7 Quasi-static engineering stress–engineering strain diagram for Plate 3.1 (as received,

no ECAE); 8 rolling passes
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Fig. A-8 Quasi-static engineering stress–engineering strain diagram for Plate 3.2 (as received, 

no ECAE); 8 rolling passes 
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Fig. A-9 Quasi-static engineering stress–engineering strain diagram for ECAE processed 

Plate 26, rolled into sheet A26; texture A; 14 rolling passes
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Fig. A-10 Quasi-static engineering stress–engineering strain diagram for the ECAE 

processed Plate 25, rolled into sheet C25; texture C; 14 rolling passes
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Fig. A-11 Quasi-static engineering stress–engineering strain diagram for ECAE processed 

plate 13; texture C
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List of Symbols, Abbreviations, and Acronyms

ARL US Army Research Laboratory

ECAE equal channel angular extrusion

Mg magnesium

q reduction of area (necking of failure)

SEM scanning electron microscopy

UTS ultimate tensile stress

εf elongation to failure
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48

1 DEFENSE TECHNICAL

(PDF) INFORMATION CTR

DTIC OCA

2 DIRECTOR

(PDF) US ARMY RESEARCH LAB

RDRL CIO L

IMAL HRA MAIL & RECORDS

MGMT

1 GOVT PRINTG OFC

(PDF) A MALHOTRA

21 DIR USARL

(PDF) RDRL WMM

J BEATTY

R DOWDING

M VAN LANDINGHAM

RDRL WMM D

R CARTER

K CHO

S WALSH

RDRL WMM E

L VARGAS GONZALES

RDRL WMM F

L DOUGHERTY

S GRENDAHL

V HAMMOND

E HORWATH

L KECSKES

T SANO

M TSCHOPP

RDRL WMP C

R BECKER

D CASEM

J LLOYD

C WILLIAMS

RDRL WMP E

M BURKINS

T JONES

P SWOBODA