Formation mechanism of partial stacking faults by incompletemixed-mode phase transformation: A case study of Fe-Ga alloys  

作　　者：Tianzi Yang Tianyu Ma Feng Liu Xiaobing Ren 

机构地区：[1]Frontier Institute of Science and Technology,State Key Laboratory for Mechanical Behavior of Materials,and MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter,Xi’an Jiaotong University,Xi’an 710049,China [2]State Key Laboratory of Solidification Processing and Analytical and Testing Center,Northwestern Polytechnical University,Xi’an 710072,China [3]Center for Functional Materials,National Institute for Materials Science,Tsukuba 305-0047,Ibaraki,Japan

出　　处：《Journal of Materials Science & Technology》2022年第22期59-64,共6页材料科学技术（英文版）

基　　金：This work was supported by the National Natural Science Foundation of China(Nos.51871174 and 51831006);the State Key Laboratory of Solidification Processing in NPU(No.SKLSP202003).

摘　　要：Partial stacking faults(PSFs) formed by incomplete mixed-mode phase transformation have been found to exhibit unfixed slip distance of closely-packed planes unlike those of the deformation-induced stacking faults(SFs) with fixed distance. Though engineering PSFs can yield appealing properties, such as the enhanced damping capacity, understanding of the interaction between lattice distortion and atomic diffusion and their influences on forming PSFs is still far from being clear. Herein we performed a case study on aged Fe-Ga alloy that undergoes a mixed-mode phase transformation from body-centered cubic(BCC)to ordered face-centered cubic(FCC). The TEM investigations showed that the faulted {111}-FCC distance of the PSFs is shorter than a/6<112> of the typical {111}-<112> SFs in deformed FCC materials and the PSFs have disordered Fe and Ga arrangements. Further studies revealed that such PSFs will not be completely dissociated at FCC twin boundaries(TBs) even after long term isothermal aging. Consequently,the formation of PSFs can be ascribed to the transformation-dependent atomic ordering and lattice shear strain of the parent BCC lattice, where the diffusion-controlled glides of the PSFs-associated dislocations will accelerate atomic diffusions due to the dislocation-pipe effect along <112>-FCC direction, but may hinder the atomic diffusions across the {111}-FCC TBs due to the retarding effect. This study may add important insight into the defects process during mixed-mode phase transformation and broaden the knowledge of the interaction between concurrently-happened lattice distortion and atomic diffusion.

关 键 词：Stacking faults Mixed-mode phase transformation DIFFUSION Lattice distortion Fe-Ga alloy 

分 类 号：TG141[一般工业技术—材料科学与工程]