Loudis J A, Baker I
Thayer School of Engineering at Dartmouth College, Hanover, New Hampshire 03755, USA.
Microsc Res Tech. 2008 Jul;71(7):489-96. doi: 10.1002/jemt.20576.
Dislocations in the spinodal alloy Fe(30)Ni(20)Mn(25)Al(25), which is composed of alternating BCC and B2 (ordered BCC) phases, have been investigated using weak-beam transmission electron microscopy (TEM). The alloy was compressed at room temperature in an as-hot-extruded state to strains of approximately 3% for post-mortem dislocation analysis. Dislocations with a/2<111> Burgers vectors were found to glide in pairs on both {110} and {112} slip planes. TEM in situ straining experiments were also performed on both the as-extruded alloy and an arc-melted alloy. The in situ straining observations confirmed that dislocations were able to pass between both spinodal phases. Partial dislocation separations were relatively wide in the BCC phase and narrow in the B2 phase. Dislocation glide, as opposed to twinning (both of which have been observed in other BCC-based spinodals), was also found to be the only room temperature deformation mechanism.
利用弱束透射电子显微镜（TEM）对由交替的体心立方（BCC）相和B2（有序体心立方）相组成的亚稳合金Fe(30)Ni(20)Mn(25)Al(25)中的位错进行了研究。该合金在室温下以热挤压态进行压缩，应变约为3%，用于事后位错分析。发现具有a/2<111>柏氏矢量的位错在{110}和{112}滑移面上成对滑移。还对挤压态合金和电弧熔炼合金进行了TEM原位应变实验。原位应变观察证实，位错能够在两个亚稳相之间通过。在体心立方相中，部分位错间距相对较宽，而在B2相中较窄。与孪生（在其他基于体心立方的亚稳合金中均观察到）不同，位错滑移也被发现是唯一的室温变形机制。
