実験報告書様式（一般利用課題・成果公開利用）（ ※本報告書は英語で記述してください。ただし、産業利用課題として採択されている方は日本語で記述していただいても結構です。 ）MLF	 Experimental Report

提出日 Date of Report

課題番号 Project No.

装置責任者 Name of responsible person

2012B0100

Kazuya AIZAWA and Stefanus HARJO

実験課題名 Title of experiment

装置名 Name of Instrument/（BL No.）

In-situ Neutron Diffraction Study on Deformation Behavior of Mg

TAKUMI (BL 19)

Alloy with Long-Period Stacking Ordered Phase

実施日 Date of Experiment

実験責任者名 Name of principal investigator

Dec. 15 2013 - Dec. 17 2013

Satoshi MOROOKA所属 Affiliation
Yokohama National University
試料、実験方法、利用の結果得られた主なデータ、考察、結論等を、記述して下さい。（適宜、図表添付のこと）
Please report your samples, experimental method and results, discussion and conclusions. Please add figures andtables for better explanation.
1. 試料 Name of sample(s) and chemical formula, or compositions including physical form.
Master ingots with a composition of Mg97Zn1Y2 (at%) and Mg89Zn4Y7 (at%) were prepared by induction melting.
And then, the as-cast ingots were extruded at 350 and 450 degree C at a reduction rate of 10:1 in air at ram
speed of 2.5mm/s, which were named as Mg12E and Mg47E, respectively [1]. The obtained Microstructure isαMg (hcp) + LPSO two-phase structure for all. The volume fraction of LPSO phase was 25 pct. and 85 pct.,
respectively which was determined by a point counting method. The scattering density of αMg phase is
6.98E+10 (cm^-2) and 7.14E+10 (cm^-2) for the extruding type of Mg12E and Mg47E alloys, respectively.
[1] K. Hagihara et al.; Intermetallics, 18(2010), 1079.

2. 実験方法及び結果 （実験がうまくいかなかった場合、その理由を記述してください。）
Experimental method and results.

If you failed to conduct experiment as planned, please describe reasons.

【Experimental method】 The in-situ TOF neutron diffraction during tensile loading was performed by using
TAKUMI (BL19). The bar type tensile test specimens for in-situ experiments with a gouge length of 15 mm,diameter of Φ5 mm were machined from the extruded Mg alloy. TAKUMI is equipped with 50kN tension tester
mounted on the diffractometer, with its loading axis
turned 45 degrees with respect to the incident beam.
Therearetwodetector banks, whichmeasuretime-resolved diffraction patterns at fixed horizontal
scattering angles of ±90 degrees. The two detectorbanks thus measure diffraction patterns from grainsoriented in axial and transverse geometry with respect
to the applied stress.

Fig. 1 Time schedule of tensile test for Mg12E.
12. 実験方法及び結果（つづき） Experimental method and results (continued)
The sampling volume for neutron diffraction is wide range at the parallel position of the tensile specimen, sothat bulky averaged information is obtained. The in-situ diffraction experiments during tensile testing wereconducted using load control (elastic region) and elongation control (plastic region), with counting times ofapproximately 1800 sec (Fig. 1).
【Experimental result】
Figure 2 shows a lattice strain determined from peakshifts of {10-10} Mg, {0002} Mg, {10-11} Mg, {11-22} Mg,{4-2-25} LPSO and {4-2-28} LPSO reflection peaks as afunction of the applied stress for Mg12E alloy. As isobserved in Fig. 2, the lattice strains of them in the axial
direction increase linearly with increasing of the appliedFig. 2 Change in lattice strain during tensilestress in the beginning of deformation indicating elastic

deformation of the Mg12E alloy in the axialregime. From the diffraction slopes, it is found so called

direction.

the diffraction young’s modulus Ehkl for [10-10] Mg,[10-11] Mg, [11-22] Mg and [4-2-25] LPSO are slightly
larger than that for [0002] Mg and [4-2-28] LPSO. The
obtained values of E10-10, E0002, E10-11, E11-22, E4-2-25 andE4-2-28 are approximately 46GPa, 51GPa, 47GPa, 47GPa,48GPa and 51GPa, respectively. Therefore, this meansthat influence of elastic anisotropy is very small. Afteryielding (= Macro yielding), in case of the Mg matrix,{10-10} Mg lattice strain increase while {0002} Mg, {10-11}Mg and {11-22} Mg decrease with increasing of the appliedstress. This implies that the {0002} Mg, {10-11} Mg and{11-22}Mg

family grains are plastically softer than

{10-10} Mg grains, resulting in stress partitioning that iscalled intergranular stresses. This result was suggested

Fig. 3 Change in lattice strain during tensilethat {0002} Mg, {10-11} Mg and {11-22} Mg family grains

deformation of the Mg47E alloy in the axial

were occurred the stress relaxation by basal slip, shear

direction.

deformation and twinning deformation. In case of theLPSO phase, [4-2-25] LPSO and [4-2-28] LPSO lattice strain increase with increasing of the applied stress. Thismeans that LPSO family grains continue the elastic deformation in spite of Mg matrix yielding. After then, this
implies that the [4-2-25] LPSO family grains are plastically softer than [4-2-28] LPSO grains, resulting in stresspartitioning. Hence, Mg12E alloy was able to estimate that Mg matrix and LPSO phase deformed to theseparation due to the dual-phase alloy.
Figure 3 shows a lattice strain determined from peak shifts of {10-10} Mg, {0002} Mg, {10-11} Mg, {11-22} Mg,{4-2-25} LPSO, {4-2-27} LPSO, {4-2-28} LPSO and {4-2-210} LPSO reflection peaks as a function of the applied stress2

for Mg47E alloy. As is observed in Fig. 3, the lattice strains of them in the axial direction increase linearly withincreasing of the applied stress as well as Fig. 2. The obtained values of E10-10, E0002, E10-11, E11-22, E4-2-25, E4-2-27,

E4-2-28 and E4-2-210 are approximately 53GPa, 54GPa, 51GPa, 54GPa, 54MPa, 50MPa, 58MPa and 53GPa,respectively. Therefore, the influence of elastic anisotropy of Mg matrix is smaller than that of LPSO phase.
And then, these values of Mg47E are larger than those of Mg12E. Because, it can be estimated that the atom
bonding of Mg47E alloy was strengthening by concentration of Zn and Y.

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