PSI - Issue 13

Naoyuki Tsutsui et al. / Procedia Structural Integrity 13 (2018) 849–854 Author name / Structural Integrity Procedia 00 (2018) 000 – 000

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This onset temperature was previously reported by Old and Trevena (1979a). It should be noted that the UTS of polycrystalline Zn specimens in contact with Ga was much smaller than those in contact with In and the Bi – In alloy when just above the onset temperature of LME, and gradually increased above 360 K. SEM micrographs of the fracture surfaces (see Fig. 5) indicated that liquid In, Bi – In, and Bi – Sn induced mainly transgranular fractures, similar to a Zn specimen cracked at liquid nitrogen temperature without an embrittler (Fig. 5(d)). Each grain displayed stepped cleavage surfaces. On the other hand, as shown in Fig. 6, liquid Ga induced intergranular fracturing at low temperatures, while transgranular fracture were more frequently observed at higher temperatures.

Fig. 5. SEM micrographs of transgranular fracture surfaces cracked at (a) 423 K in contact with liquid In, (b) 353 K in contact with the Bi – In eutectic, (c) 428 K in contact with the Bi – Sn eutectic, and (d) 77 K without embrittlers, for comparison.

Fig. 6. SEM micrographs of fracture surfaces cracked in contact with liquid Ga at (a) 308 K and (b) 423 K.