Status of Magnesium Research & Developmentin Korea
Kwang Seon Shin
Professor and Director
Magnesium Technology Innovation Center
School of Materials Science and Engineering
Seoul National University, Seoul 08826, Korea

Outline◼ Background◼ World Premier Materials (WPM) Project on Mg Alloys◼ Korea Institute of Materials Science (KIMS)◼ Magnesium Technology Innovation CenterSeoul National University◼ Additive Manufacturing of Mg Alloys (Daegun & KMTRA)

CO2 Emissions◼ CO2 Emissions: Transportation > 20%

CO2 Emission in US by Economic Sector (2012)
http://www.epa.gov/climatechange/ghgemissions/sources/transportation.html

Total of 35.3 Billion Tons CO2 Produced in 2013

Magnesium Alloys
Advantages of Magnesium Alloys⚫ The Lightest among All Structural Metals⚫ ….......

Disadvantages⚫ Cost⚫ Formability⚫ Strength⚫ Corrosion Resistance⚫ Anisotropy⚫ ….......

Twin Roll Casting Process◼ Advantages> Low Production Cost
> Fine Microstructure> …..

Schematic Diagram of Twin Roll Casting
M. Ferry, Direct Strip Casting of Metals and Alloys, Cambridge, UK, 2006

Status of POSCO Mg Sheet Project◼ 2002.08 :Proposal for Mg Project to POSCO by SNU◼ 2003.11 :Mg Sheet Project Team Established at POSCO/RIST◼ 2004.01 :Consultant for Mg Project for POSCO/RIST◼ 2004.01 :Construction of Pilot Plant for Mg Sheet◼ 2004.11 :Completed Mg Sheet Pilot Plant◼ 2005.03 :Production of Mg Sheet (Width 600mm)◼ 2006.08 :Start Construction of Mg Sheet Plant ($60 Million)◼ 2007.07 :Commercial Production of Mg Sheet (3,000 ton/year)◼ 2010.04 :Initiation of Mg Smelting Business◼ 2013.04 :Production of 2,000mm Wide Cast Strip◼ 2016.10 : Investment of >$100M for Wide Strip Rolling Facility◼ 2019.03 : Completion of Rolling Facility for Wide Mg Strip

Strip Caster

Reversible Warm MillCleaning Line

Sheet Slitting LineComparison between TRC Process and Conventional Process▪ Twin Roll Casting & Continuous Rolling
MeltingFurnace

Strip Caster

POSCO WPM

Coil Preheater

Reversible Warm MillMg Strip▪ Conventional Process: DC Casting + Tandem Rolling
Melting/Holding
FurnaceReheatingFurnace

Hot Rolling
MillAnnealing
Furnace

Irreversible WarmRolling MillD/C Pit※ Benefit of Strip Casting✓ Continuous Process ⇒ Better Productivity & Lower Cost
✓ Reversible Warm Mill ⇒ Finer Microstructure<Wide StripCaster><Warm RollingMill>World Premier Materials (WPM) Project on Mg Alloys

Project TitleLight Magnesium Materials for Transportation Industry

Project Leader

POSCORenault Samsung, Ssangyong Motors, Volkswagen, Hyundai Motors,KMI, Solution Lab, Sungwoo Hitech, Shinyoung, MS Auto Tech, KSM
Participating
Organization

Hyundai Sungwoo Metal, Dongnam Precision Co.,
Nohroo Coil Coating, KC Chemical, GlowOne, MAGNA, KIMS, RIST
※ 16 Companies, 2 Research Institutes

Project Period

2010. 9 ~ 2019. 3

8 / 12

Research Objectives

Formability

Cost

New Alloy Development

Corrosion
Resistance

Cost Reduction

Mg Surface Treatment Technology

9 / 12POSCO Twin Roll Cast 2,000mm Magnesium SheetLuggage Retainer : Renault-Samsung SM7 Nova

➢ Component : Between the backof the rear seat and the trunk➢ Using AZ31B 1.4t sheet (POSCO)➢ Weight Saving : 2.2kg
Steel (3.6kg) → Mg (1.4kg)

KMTRA

11

Roof Panel : Porche 911 GT3 Rs

POSCO Mg Sheet

KMTRA

Width : 1,000mm
Weight : 3.65Kg (Al sheet : 4.72kg)

12

LG Gram Notebook 15Z970-GPB5ML

Application of Wrought
Mg Alloys

14

Ultra Light Laptop by Magnesium SheetModel

NEC Z LZ550
2013 (Japan)

LG gram14
2015 (Korea)

LG gram 15Z 960
2015 (Korea)

LG All Day gram
15ZD970
2017 (Korea)

Samsung Always
NT900X5N-X58
2017 (Korea)

ScreenSize

13.3 inch

14.2 inch

15.6 inch

15.6 inch

15 inchWeight875g

980g

980g

1,090g1,250gMagnesium
Application

Mg-Li a\Alloy(D Cover)CarbonMagnesium andMg-Li Alloy

Magnesium
Sheet(D Cover)

MagnesiumSheet(D Dover)

Magnesium
Sheet(C, D Cover)

E-form (High Formable POSCO Magnesium Sheet)
KMTRA

15Alloy
Alloy
DevelopDevelopment
ment

Processing
Technology

PracticalApplication

4.02 mm
AZ31 (Commercial Alloy)

8.18 mm

AZXW3100 (New Alloy)

Metal powder
New Grain refiner

Solidified Mg and AlGrain refiner

Grain refinerparticles surroundedsolidified Al and Mg

Mg alloy melt

Mg alloy melt

Severe plastic deformation at RTExtruded

High Performance Magnesium Alloys⚫ Low Cost
⚫ High Formability⚫ High Strength⚫ High Corrosion Resistance⚫ Nonflammability⚫ Isotropic Mechanical Properties⚫ High Modulus⚫ Low Density⚫ ….......

Slip Modes in Magnesium--(1101)(1102)-(1122)(1011)-(2111)

S--(1100)(1100)

CA

B(0001)-

1/3[1120]

Basal Plane<a> SlipType ofDislocation

Number of Systems(Independent)
3 (2)a (AB)c (ST)c+a (ST+AB)

3 (2)Burgers Vector

1/3<1120>

Magnitude ofBurgers Vector

Prism-I

6 (4)Pyramidal-I

3 (2)Prism-I

3 (2)
6 (5)

<0001>|c|=5.211

1/3<1123>{|a|2+|c|2}1/2=6.120<c+a> Slip
Slip SystemBasal|a|=3.209--

1/3[1123]{0001} <1120>- <1120>{1010}- <1120>{1011}- <0001>{1010}

Prism-II- <0001>{1120}

Pyramidal-II- <1123>{1122}

Research Programs at Magnesium Technology Innovation Center◼ Development of Advanced Mg Alloys➢Computer Simulation for Phase Formation by Thermodynamic
Calculations and Flow/Solidification Behavior➢ High Strength/High Formability Alloys➢ High Temperature Alloys➢ Corrosion Resistant Alloys and Biodegradable Materials◼ Characterization of Microstructure/Texture and MechanicalProperties➢➢➢➢➢

Prediction of Deformation Behavior by Crystal Plasticity Simulation
Manufacturing and Characterization of Mg Single Crystals
Analyses of Microstructure/Texture, Dislocation, Twin
Mechanical Properties and Corrosion Behavior
Creep and Fatigue Properties◼ Development of Twin Roll Casting/Extrusion/Rolling Processes◼ Semi-Solid Processing of Mg Alloys◼ Surface Treatment: Plasma Electrolytic Oxidation Coating◼ Development of Mg Die Casting Components for Automobile andElectronic Industries

Development of Twin Roll Cast Mg Alloys
with High Strength and High Formability

Solidification Behavior & Segregation
AZ31

Increasing Roll Speed: Increasing Exit Temp.
◼ Factors Affecting Solidification

Behavior> Thermal Properties of Alloys> Freezing Range of Alloys> Melt Temperature> Setback Distance> Roll Speed> Roll Separating Force◼ Development of New Mg

Alloys for TRC Process◼ Optimization of Processing
Parameters

P. Thomas, Continuous Casting of Aluminium Alloys, Institute of Physics, 2003, UK, 26-47

ICME for Alloy Design and Materials Processing
PandatTM

JMatProTM

LaboTex

Thermodynamic Calculations Thermodynamic Calculations

Texture Analysis

Prediction of Stable Phases

ODF Calculation

Alloy Design

Prediction of Material
Properties, Alloy Design

VPSC-GA
Texture Simulation Based on
Visco-Plastic Self-Consistent
Model and Genetic Algorism
Prediction of Texture & StressState during Deformation

PandatTM 7.0

Guide for Alloy Design

DEFORMTM

AnyCastingTM
Analysis of Flow andSolidification Behavior
Die Design, Defect Analysis

Simulation of Deformation Behavior during MaterialProcessing by FEM
Simulation ofExtrusion andTwin Roll Strip
Casting Processes
Guide for Process
Development

Manufacturing Process for TRC Plates◼ Fabrication of TRC Mg Alloy Plates> Thickness: 3.0~3.3mm> Width: 50~65mm> Length: 2,500~3,500mm◼ Development of New TRC Mg Alloys with Low Segregation & Improved

Formability

1

1

0.1

0.1

0.1

0.01

0.01

0.01

1E-3

1E-3

1E-3

Liquid-Mg
Mg17Al12

1E-4

1E-5

Al11Mn4

1E-6

400

500

600

o700

800

900

1E-5

Al11Mn4

1E-7(Mg, Al)2Ca400

500

600

o700

800

900

0.010.010.01

1E-3

Liquid-Mg
Mg17Al12

1E-4
1E-5

Al8Mn5
Mn3(Al,Si)10400

500

600

o700

Temperature ( C)

800

1E-6

Al4Sr

1E-7
1E-8

900

800

900

Liquid-Mg
Mg17Al12
Al8Mn5

1E-7

Al38Mg58Sr4< AS60>

1E-9
300

700

1E-5

Al11Mn4

Mg2Si

1E-8

o

1E-4

Al8Mn5

1E-6

Al11Mn4

600

1E-3

1E-3

Liquid-Mg
Mg17Al12500

Mole Fraction

0.1

Mole Fraction

0.1

Mole Fraction

0.1

1E-7

400

Temperature ( C)11E-6

< AC60>Temperature ( C)

1

1E-5

Al7Cu3Mg6

1E-9300

11E-4

Al11Mn4

1E-7
1E-8< AX60>Temperature ( C)

Al8Mn5

1E-6

1E-6

1E-9300

Liquid-Mg
Mg17Al12

1E-4

Al8Mn5

1E-8

< A6>

1E-8300

Liquid-Mg
Mg17Al12

1E-4

Al8Mn5

1E-5

1E-7

Mole Fraction

1Mole Fraction

Mole Fraction

Solidification Behavior of Mg-6Al-X (Scheil Condition)

Al11Mn4

1E-8< AJ60>

1E-9300

400

500

600

o700

Temperature ( C)

800

900

< AZ60>

1E-9300

400500600

o700

Temperature ( C)

800

900

Thermal Properties of Mg-6Al-X Alloys for TRC Simulation
Thermal Conductivity (W/m•K)

Specific Heat (J/g•K)

15A6AX60
AC60
AS60
AJ60
AZ00

1296300200400o180
A6AX60
AC60
AS60
AJ60
AZ00

160140120

Twin Roll Strip Casting80
600600200600o<Thermal Conductivity>
1.0
A6AX60
AC60
AS60
AJ60
AZ60

300200

A6AX60
AC60
AS60
AJ60
AZ60

0.8

Solid Fraction

Latent Heat (J/g)

400

Temperature( C)

4000.60.4

1000.20400500

600o700> Melt Temp.: 670oC> Roll Speed: 3mpm

100

Temperature( C)<Specific Heat>◼ Simulation Conditions

0.0300400500

o600

Temperature( C)

Temperature( C)<Latent Heat><Solid Fraction>

700

Simulation of Liquid Fraction During TRC Process
LiquidFraction

A6RollDistance

Distance toRoll Nip Point
A6: 64.6mm

AX60

AX60: 48.9mm
AC60

AC60: 49.1mm
AS60

AS60: 36.8mm
AJ60

AJ60: 58.2mm
AZ60

AZ60: 34.6mm

Microstructure of TRC Mg-6Al-X Alloys
CDA6

AX60

AC60

ND◼ Segregation Factors> Freezing Range> Second Phase> Solidification Behavior> Partition Coefficient

Segregation

Segregation
Segregation

AS60

AZ60

AJ60Segregation
Segregation

Mg Alloys

Segregation

A6AX60
AC60
AS60
AJ60
AZ60

CenterlineSegregation %1.92.12.0
2.72.23.4

Centerline Segregation Area and Melt to Roll Nip DistanceCenterline Segregation Area (%)

5432

A6AX60
AC60
AS60
AJ60
AZ60

1010305070

Melt to Roll Nip Distance (mm)90Photographs of Mg-6Al-X Alloys after Erichsen Tests
Pre-heating: 350oC

Pre-heating: 450oC
A6: 3.3mm

A6: 4.8mm

AX60: 3.4mm

AX60: 5.3mm

AC60: 3.5mm

AC60: 5.1mm

AS60: 3.3mm

AS60: 6.4mmAJ60: 3.4mm

AJ60: 5.7mm

AZ60: 3.4mm

AZ60: 5.2mm

Mg-Zn-X-Ca TRC Plates

Z4ZX40ZAX400AT63ZWX400ZCX400ZSX400

Photographs of Mg-Zn-X-Ca Alloys after Erichsen Tests◼ Erichsen Tests> Punch Diameter: 20mm
> Punch Speed: 5mm/min.
Z4 (IE: 3.8)

ZX40 (IE: 7.2)

ZAX400 (IE: 7.5)

ZWX400 (IE: 7.6)

ZCX400 (IE: 8.0)

ZSX400 (IE: 3.8)

VPSC Simulation Results of Mg-Zn-X-Ca Alloys

500400300

200Threshold Stress (MPa)

Simulation of Flow Stress(Mg-Zn-X-Ca Alloys)|Stress| (MPa)

400(Experiment)
Z4
ZX40
ZAX400ZWX400ZCX400ZSX400(Simulation)
TensionComp.

1000051015|Strain| (%)

2025(Modes)Basal <a>Prism. <a><c+a>Tensile Twin
Compressive
Twin(Alloy)Z4
ZX40
ZAX400ZWX400ZCX400ZSX400

300

200

100

00.00

0.05

0.10

0.15

0.20

0.25

Accumulated Shear Strain

0.30

Activities of Deformation Mode of Mg-Zn-X-Ca Alloys
Tension(Modes)Basal <a>Prism. <a><c+a>Tensile Twin
Compressive
Twin(Alloy)Z4
ZX40
ZAX400ZWX400
ZCX400ZSX4000.80.60.4

0.2

0.00.00

0.05

0.10

0.150.20|True Strain|

0.250.30

1.0

Relative Acitivity

Relative Acitivity

1.0Compression(Modes)Basal <a>Prism. <a><c+a>Tensile Twin
CompressiveTwin(Alloy)Z4
ZX40
ZAX400ZWX400ZCX400ZSX4000.80.60.4

0.2

0.00.00

0.05

0.10

0.15

0.20

0.25

|True Strain|◼ Deformation Modes> Tension: Initially Basal <a> Slip & Later Prismatic <a> Slip Activated> Compression: More Basal <a> Slip Activated for High Formability

0.30Relationship Between Erichsen Value and Yield Strength
Pure Mg [1]Mg-0.2Ce [1]Mg-1.5Mn [2]Mg-1.5Zn [3]Mg-1.5Zn-X [3, 4]
Mg-2.5Zn-0.2Ce [5]AZ31 [6]AM60 [7]AZ61 [7, 8]
AZ80 [9]Mg-1Zn-xGd [10]Mg-4Y-3RE [11]Mg-9Li-1Y [12]Mg-5Li-3Al-1Zn [13]New Mg-Zn-X-Y-Ca

Erichsen Values (mm)

1210
ZW20
ZE(Ce)20
Twin Roll Cast
AM60
LAZ531 ZCX400

86M2ZX20
GZ31E0ZE20
GZ21

ZWX400
AZ61 ZX40ZE20

AZ61WE434Pure Mg
Z2ZSX400Z4M2

After Aging

ZW21

AZ61

LW91

ZE(Ba)202ZAX400

AZ31AZ80
AZ31AZ31Z2
WE43100150200

Yield Strength (MPa)[1]. Y Chino et al., MSE A, 494 (2008), pp.343-349[2]. K Suzuki et al., Mater. Trans., Vol.54 (2013), pp.392-398[3]. M Yuasa et al., Acta Mater., Vol.83 (2015), pp.294-303[4]. ZX Cai et al., Rare Met., Vol.32 (2013), pp.441-447[5]. Y Chino et al., MSE A, Vol.528 (2010), pp.566-572[6]. Y Chino et al., Scripta Mater., Vol.60 (2009), pp.447-450[7]. X Huang et al., J. Alloy Compd., Vol.632 (2015), pp.94-102[8]. X Huang et al., Scripta Mater., Vol.60 (2009), pp.651-654[9]. X Huang et al., MSE A, Vol.508 (2009), pp.226-233[10]. D Wu et al., J. Alloys Comp., Vol.509 (2011), pp.2856-2863[11]. X Huang et al., MSE A, Vol.538 (2012), pp.281-287[12]. H Taduda et al., Mater. Trans., Vol.44 (2003), pp.2266-2270[13]. Q Yang et al., Int. J. Mater. Forum, (2014)

250300Fundamental Study on
Deformation Behavior of Mg Single Crystals

The Largest Magnesium Single Crystal!

Mg Single Crystal
150mm(L) × 58mm(Dia.)Experimental Procedures
Single Crystal Growing

Pattern Acquisition & Indexing

Experimental Condition:
Furnace : 750oC
Ar, Water Supply
Speed : 5 mm/hr (RPM = 70)

StereographicProjection

X-ray Laue Machine
Bridgman Method

Mechanical Test

Microstructure Characterization & Texture Measurement

F20
R & B UNITECH

X’Pert PRO MRD

SU70+TSL6.1(EBSD)

Various Sample Orientations Used for Mechanical Testing
Orientation A (S)LD[40 20 20 37]

Orientation B (S)Slip System

Schmid Factor

BasalLDSlip System

Schmid Factor

0.50

Basal0Prismatic

0.22

Prismatic

0.5

c+a0.28

c+a0.42

Tensile Twin

0.25

Tensile Twin

0.47

Compression Twin

0.29

Compression Twin

0.39

[90 123 33 0]

Orientation C (M)LD[0 1 1 0]

Slip System

Schmid Factor

Basal

0

Prismatic

0.43

c+a0.33

Tensile Twin

0.50

Compression Twin

0.42

VPSC-GA
Simulation

S: Single Slip, M: Multiple Slip

Tensile Direction ⁄⁄ [40 20 20 37]: Basal Slip Activation
Normal Direction (ND)
Loading Direction (LD)Transverse Direction (TD)

298K
413K
453K
493K
533K
573K
613K653K
693K
733K

Orientation A(0002)

3Stress (MPa)45o(1010)

210LD0246Strain (%)
NDTD

810

Tensile Direction ⁄⁄ [90 123 33 0]: Prismatic Slip Activation
Normal Direction (ND)
Loading Direction (LD)150

Transverse Direction (TD)

298K
413K
453K
493K
533K
573K
613K
653K
693K
733K

Orientation B

Stress (MPa)(0002)(1010)
45o

100

500LD02

46

Strain (%)
ND

TD

810

Loading Direction ⁄⁄ [0 1 1 0]
LD

Normal Direction (ND)

Slip System

Schmid Factor

Basal0Prismatic0.43

Pyramidal I0.38Pyramidal II0.30

c+a0.33

Tensile Twin

0.50

Compression Twin

0.42

Loading Direction (LD)[0 1 1 0]

Transverse Direction (TD)(0002)

150

298K
413K
453K
493K
533K
573K
613K
653K
693K
733K

Orientation C

Stress (MPa)(1010)

10050

LD

ND

TD

002

46

Strain (%)

810

Procedure for VPSC-GA Simulation<VPSC><GA>

Initial Texture
Uniaxial Tension
Uniaxial Compression

Strain Hardening &Twin Reorientation
Parameters
Execution of
VPSC Simulation
Comparison ofStress-Strain Curve

Range of
Hardening Parameters(Input Parameters)
Generation of
Candidate Solutions(Mating Process)
Crossover & Mutation ofSolutions

Comparison ofDeformation Texture

Selection of Better Solutions

Are They Similar
to Exp. Results?

Calculation ofFitness

Yes(Deformation Mechanism)
CRSS Value Derivation
ActivityEffects of Temperature on CRSS for Slip and Twinning Modes

CRSS, c (MPa)120
Basal <a>Prismatic <a><c+a>{1012} Twin
{1011} Twin

9060300300

400

500

600

Temprature (K)700Y Sections for Orientation A, B & CCenterc[1 2 1 0] // PD

Side[0 0 0 1] // X
IE: 2.0mm C [1 0 1 0] // Yc[1 0 1 0] // PD

Ac[0 0 0 1] // X
[1 2 1 0] // Y

IE: 6.8mm[777 0 777 829] // PD

B[777 0 777 829] // X
[1 2 1 0] // Y

IE: 2.5mm

C.S. Hyun et al., Acta Mater. (2018)

Magnesium 3D Printer (Daegun Tech & KMTRA)
60x60x80
0.04mm~0.08mm
50 um
Up to 7.0m/s
Yb-fiber Laser 200W
1,540x1,215x2,000
1,500kg
AC 220V 30A
Max 2.2 kWArgon

3D Printing of Mg Alloy

3DP of Magnesium Alloys

3DP of Magnesium Alloys

Thanks for your kind attention !

The 10th International Conference on Magnesium
Alloys and their Applications
Jeju Island, Korea