Abstract
We systematically compared the mechanical properties of CrCoNi,a recently emerged prototypical medium-entropy alloy(MEA)with face-centered-cubic(FCC)structure,with hallmark FCC alloys,in par-ticular,the well-known austenitic 316L and 316LN stainless steels,which are also concentrated single-phase FCC solid solutions and arguably next-of-kin to the MEAs.The tensile and impact properties,across the temperatures range from 373 K to 4.2 K,as well as fracture toughness at 298 K and 77 K,were documented.From room temperature to cryogenic temperature,all three alloys exhibited similarly good mechanical properties;CrCoNi increased its tensile uniform elongation and fracture toughness,which was different from the decreasing trend of the 316L and 316LN.On the other hand,the stainless steels showed higher fracture toughness than CrCoNi at all temperatures.To explain the differences in macro-scopic mechanical properties of the three alloys,microstructural hardening mechanisms were surveyed.CrCoNi MEA relied on abundant mechanical twinning on the nanoscale,while martensitic transformation was dominant in 316L at low temperatures.The deformation mechanisms in the plastic zone ahead of the propagating crack in impact and fracture toughness tests were also analyzed and compared for the three alloys.
基金项目
This work was financially supported by the Ministry of Sci-ence and Technology of China(2019YFA0209900)
This work was financially supported by the Ministry of Sci-ence and Technology of China(2017YFA0204402)
NSFC Basic Science Center Program for"Multiscale Problems in Nonlinear Mechanics"(Grant 11988102)
NSFC(11972350)
NSFC(11890680)
and the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant XDB22040503)
NETL
NSTL
维普
万方数据