Compositional complexity dependence of dislocation density and mechanical properties in high entropy alloy systems
Compositional complexity dependence of dislocation density and mechanical properties in high entropy alloy systems
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DOI：
10.1016/j.pnsc.2020.07.002
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发表时间：
2020-08-01
影响因子：
4.7
通讯作者：
Han, J.
中科院分区：
文献类型：
--
作者：
Thirathipviwat, P.;Song, G.;Han, J.
本文对FeNiCoCrMn和TiNbHfTaZr高熵合金（HEAs）分别为单相fcc和bcc固溶体的冷塑性变形后位错积累和力学性能进行了定量分析。为了研究组成复杂度从一元到五元对位错积累和塑性变形后力学性能的影响，研究了两种HEA5的单固溶相成形亚合金。所有研究的样品在不经过中间退火的情况下，均表现出较大的塑性变形能力。所有研究样品的位错密度，由Williamson-Hall方法在同步加速器x射线衍射图上测定，根据合金成分的不同，在10(14)- 10(15)m（-2）之间。塑性变形后的位错密度水平不仅受组成元素数量的影响，而且晶格畸变和层错能、模量失配、熔点等固有性质也影响位错的储存。由于位错运动的阻力，位错密度的高低决定了机械性能的高低。研究样品的硬度和屈服抗压强度与位错密度成正比。
This study focuses on a quantitative analysis of dislocation accumulation after cold plastic deformation and mechanical properties of FeNiCoCrMn and TiNbHfTaZr high entropy alloys (HEAs) which are single phase fcc and bcc solid solutions, respectively. In order to study the role of compositional complexity from unary to quinary compositions on dislocation accumulation and mechanical properties after plastic deformation, the single solid solution phase forming sub-alloys of the two HEA5 were investigated. All studied samples revealed a large plastic deformability under cold-rotary swaging process by 85-90% area reduction without intermediate annealing. The dislocation density of all studied samples, determined by Williamson-Hall method on synchrotron X-ray diffraction patterns, were between 10(14) - 10(15) m(-2) dependent on the alloy composition. The level of dislocation density after plastic deformation is not only affected by the number of constituent element but the lattice distortion and intrinsic properties in terms of stacking fault energy, modulus misfit, and melting point also impact the dislocation storage. The level of dislocation density determines the level of mechanical properties because of a resistance to dislocation motions. The hardness and yield compressive strength of the studied samples are proportional to the level of dislocation density.