PSI - Issue 23

Yoshikazu Nakai et al. / Procedia Structural Integrity 23 (2019) 83–88 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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Fig. 5. Inverse pole figure (IPF) maps obtained by EBSD analysis.

contrast tomography (RCT). The displacement rate was 1 μ m/min and each DCT data acquisition time was 75 min. 4. Experimental results and discussion

EBSD analysis

To clarify twinning and detwinning behavior under cyclic loading, compression stress exceeded the yield stress was applied, then tensile stress was applied to a sample. The change of crystallographic orientation is shown in Fig. 5, where Fig. (a-1) and (a-2) shows the result before first loading, and (a-2) is the enlargement of the white framed region in (a-1). Figures (b) and (c) are the same site of Fig. (a-2), where Figs. (b) and (c) were obtained unloading after compression and after tensile loading as shown in the upper right figure in Fig. 5. As shown in Fig. (b), twin deformation can be recognized, and detwinning was occurred as shown in Fig. (c). Low magnification IPF maps of Fig. 5 (a) and (b) are shown in Fig. 6, where many twin crystals formed after the compression loading.

DCT measurement

Reconstruction image of the present magnesium alloy by DCT is shown in Fig. 7. The shape of grains is successfully reconstructed although some inaccuracy of location of each grain is observed. To determine the

Fig. 6. Low magnification IPF maps (a) before and (b) after compression yielding.