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 stack-ing 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 diffu-sion 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 com-pletely 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.

Tianzi Yang;Tianyu Ma;Feng Liu;Xiaobing Ren

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;State Key Laboratory of Solidification Processing and Analytical and Testing Center,Northwestern Polytechnical University,Xi'an 710072,China;Center for Functional Materials,National Institute for Materials Science,Tsukuba 305-0047,Ibaraki,Japan

材料科学技术（英文版）

[1]Tianzi Yang;Tianyu Ma;Feng Liu;Xiaobing Ren-.Formation mechanism of partial stacking faults by incomplete mixed-mode phase transformation:A case study of Fe-Ga alloys)[J].材料科学技术（英文版）,2022(22):59-64

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