Micropillar compression deformation of single crystals of Fe3Ge with the L12 structure
Micropillar compression deformation of single crystals of Fe3Ge with the L12 structure
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L12结构Fe3Ge单晶的微柱压缩变形
DOI：
10.1016/j.actamat.2021.116779
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发表时间：
2021
期刊：
影响因子：
9.4
通讯作者：
Inui Haruyuki
中科院分区：
文献类型：
--
作者：
Chen Zhenghao;Inui Haruyuki
通过微柱压缩实验研究了L12结构Fe3Ge单晶在室温下的塑性变形行为与晶体取向的关系。在Fe3Ge中，除了(010)滑移外，还首次观察到(111)滑移。(111)[101]滑移的临界可分辨剪应力(CRSS)通过外推强度随尺寸变化到“整体”尺寸估算为~240 Mpa，几乎是类似估计的(010)[101‘]滑移(~40 Mpa)的6倍。B=[101]的超晶格位错的离解方案被证实为(010)和(111)上的APB(反相界)型，而不是先前对(111)上SISF(超晶格本征层错)方案的预测，因为预期的APB不稳定性。当在(010)面上滑动时，超晶格位错没有任何择优取向(表明室温下摩擦应力较低)，而在(111)面上滑动时，观察到超晶格位错沿其螺旋方向的排列。这是由于热激活的交叉滑移形成了Kear-Wilsdorf锁，这表明在许多其他L1-2化合物中观察到了屈服应力异常，如Ni3Al。根据实验结果((111)和(010)上的APB能量和(111)和(010)滑移的CRSS值)，讨论了Fe3Ge中可能发生的一些重要的形变特征(如没有SISF偶解离和发生屈服应力异常)。
The plastic deformation behavior of single crystals of Fe 3 Ge with the L1 2 structure has been investigated at room temperature as a function of crystal orientation by micropillar compression tests. In addition to slip on (010), slip on (111) is observed to occur in Fe 3 Ge for the first time. The CRSS (critical resolved shear stress) for (111)[10 1¯] slip, estimated by extrapolating the size-dependent strength variation to the ‘bulk’size, is~ 240 MPa, which is almost 6 times that (~ 40 MPa) for (010)[10 1¯] slip similarly estimated. The dissociation scheme for the superlattice dislocation with b=[10 1¯] is confirmed to be of the APB (anti-phase boundary)-type both on (010) and on (111), in contrast to the previous prediction for the SISF (superlattice intrinsic stacking fault) scheme on (111) because of the expected APB instability. While superlattice dislocations do not have any preferential directions to align when gliding on (010)(indicative of low frictional stress at room temperature), the alignment of superlattice dislocations along their screw orientation is observed when gliding on (111). This is proved to be due to thermally-activated cross-slip to form Kear-Wilsdorf locks, indicative of the occurrence of yield stress anomaly that is observed in many other L1 2 compounds such as Ni 3 Al. Some important deformation characteristics expected to occur in Fe 3 Ge (such as the absence of SISF-couple dissociation and the occurrence of yield stress anomaly) will be discussed in the light of the experimental results obtained (APB energies on (111) and (010) and CRSS values for slip on (111) and (010)).