Han W Z, Cheng G M, Li S X, Wu S D, Zhang Z F
Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China.
Phys Rev Lett. 2008 Sep 12;101(11):115505. doi: 10.1103/PhysRevLett.101.115505. Epub 2008 Sep 11.
Microtwins and stacking faults in plastically deformed aluminum single crystal were successfully observed by high-resolution transmission electron microscope. The occurrence of these microtwins and stacking faults is directly related to the specially designed crystallographic orientation, because they were not observed in pure aluminum single crystal or polycrystal before. Based on the new finding above, we propose a universal dislocation-based model to judge the preference or not for the nucleation of deformation twins and stacking faults in various face-centered-cubic metals in terms of the critical stress for dislocation glide or twinning by considering the intrinsic factors, such as stacking fault energy, crystallographic orientation, and grain size. The new finding of deformation induced microtwins and stacking faults in aluminum single crystal and the proposed model should be of interest to a broad community.
利用高分辨率透射电子显微镜成功观察到了塑性变形铝单晶中的微孪晶和堆垛层错。这些微孪晶和堆垛层错的出现与特殊设计的晶体取向直接相关，因为之前在纯铝单晶或多晶中未观察到它们。基于上述新发现，我们提出了一个通用的基于位错的模型，通过考虑诸如堆垛层错能、晶体取向和晶粒尺寸等内在因素，根据位错滑移或孪生的临界应力来判断各种面心立方金属中变形孪晶和堆垛层错形核的倾向性。铝单晶中变形诱导微孪晶和堆垛层错的新发现以及所提出的模型应该会引起广泛关注。
