This paper investigates the γ→β phase transformation in a β-solidifying γ-TiAl alloy (Ti-42.9Al-4.6Nb–2Cr, at. %), by means of SEM and TEM. The results show that part of β/γ phase interface is flat, and TEM observations reveal that stacking faults pairs sometimes act as the β/γ phase interface in isothermally compressed samples. The γ→β phase transformation was a diffusional process, and was mainly governed by diffusion of Ti, Al and Cr. The occurrence of stacking faults pairs during γ→β phase transformation at the β/γ phase interface was related to low SISF energy and sluggish Nb diffusion.

中文翻译：

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Ti-42.9Al-4.6Nb–2Cr中的γ→β相变

本文通过SEM和TEM研究了β凝固γ-TiAl合金（Ti-42.9Al-4.6Nb–2Cr，at。％）中的γ→β相变。结果表明，β/γ相界面的一部分是平坦的，而TEM观察表明，在等温压缩样品中，叠层断层对有时会充当β/γ相界面。γ→β相变是一个扩散过程，主要受Ti，Al和Cr的扩散控制。β/γ相界面在γ→β相变过程中出现的叠层断裂对与低SISF能量和缓慢的Nb扩散有关。