Abstract
It is well documented that the strain rate sensitivity(m)increases at refined grain size for face-centered cubic(FCC)metals and alloys.Through a series of nanoindentation testing,however,we experimentally demonstrated a striking departure from conventional FCC metals that CoCrFeMnNi high entropy alloy(HEA)with FCC lattice structure exhibits monotonously decreased m as grain size reduced from～30.3μm to 7.2 nm.Moreover,the apparent activation volume v*,which generally shows an opposite trend of m,exhibited the identical decreasing trend with reduced grain size as that of m.Such an unusual trend of m and its correlation with v* in the FCC HEA alloys can be understood by a distinct deformation-mechanism-transitions and unique dislocation morphology evolution that differs from conventional FCC metals.
基金项目
This work was financially supported by the Natural Science Foundation of Shaanxi Province(2019TD-020)
Natural Science Basic Research Plan in Shaanxi Province of China(Nos.2020JM-41)
Natural Science Basic Research Plan in Shaanxi Province of China(2020JM-33)
and the National Natural Science Foun-dation of China(51471131)
NETL
NSTL
维普
万方数据