摘要
Nanocrystalline alloys often exhibit unusual thermal stability as a consequence of kinetic and thermodynamic barriers to grain growth.However,the physical mechanisms governing alloy stability need to be identified.In this work,we found that grain boundary(GB)relaxation renders Ni-W alloyed films relatively stable at low annealing temperature,while twinning-mediated grain growth occurs via dislocation-GB/twin boundary(TB)interactions as the annealing temperature increases.At a relatively low temperature,TB strengthening plays a dominant role in plastic deformation,whereas precipitation strengthening gradually controls the deformation mechanism with the increase of annealing temperature.Our findings provide evidence for improving mechanical property through alloying and microstructure design,and have a crucial guiding significance in material selection and miniaturized applications such as Micro Electro Mechanical Systems.
基金
supported by the National Natural Science Foundation of China(Grant Nos.92163201,52431006,52441407,U23A6013,92360301 and U2330203)
the Shaanxi Province Innovation Team Project(2024RS-CXTD-58)
the Shaanxi Province Youth Innovation Team Project(22JP042)
the Natural Science Basic Research Plan in Shaanxi Province(2022JQ-460)
the Fundamental Research Funds for the Central Universities(xtr062024006,xtr022019004 and xzy022022024).
