Effects of high pressure torsion on microstructures and properties of an Al0.1CoCrFeNi high-entropy alloy
Effects of high pressure torsion on microstructures and properties of an Al0.1CoCrFeNi high-entropy alloy
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DOI：
10.1016/j.msea.2015.12.085
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发表时间：
2016-02-08
期刊：
影响因子：
6.4
通讯作者：
Liu, R. P.
中科院分区：
文献类型：
--
作者：
Yu, P. F.;Cheng, H.;Liu, R. P.
采用高压扭转（HPT）技术，在6 GPa压力下，通过1转和2转，研究了Al0.1CoCrFeNi高熵合金（HEA）的组织和性能的演变。在室温下，HEA的塑性变形机制包括低应变下的位错滑移和高应变下的孪生。平面位错在正常的面心立方滑移系{111）（110）上滑移，形变孪晶的厚度从几个纳米到40 nm不等，并伴有二次孪晶。Al0.1CoCrFeNi HEA的硬度从热等静压（HIP）状态下的135 Hv增加到HPT处理后的约482 Hv。与传统合金相比，HEAs具有相对高的初始硬度和高的加工硬化。通过纳米压痕技术测定了经HPT处理的HEA的抗蠕变性。随着晶粒尺寸的减小，激活体积减小，变形机制由位错滑移转变为晶界滑移，应变速率敏感性增大。研究结果给出了单相HEA在室温下的塑性变形机制和力学性能演变规律。(C)2015爱思唯尔B. V.保留所有权利。
High pressure torsion (HPT) under a pressure of 6 GPa through 1 and 2 revolutions have been used to follow the evolution of microstructures and properties in an Al0.1CoCrFeNi high-entropy alloy (HEA). The plastic-deformation mechanisms of the HEA include dislocation slip at low strains and twinning at high strains at room temperature. The planar dislocation slip on the normal face-centered-cubic slip system, {111)(110), and nanoscaled deformation twins with a thickness from several nanometers to 40 nm, accompanied with some secondary twins. The hardness of the Al0.1CoCrFeNi HEA increases from 135 Hv at hot-isostatic pressed (HIPed) state to about 482 Hv after HPT processing. The HEAs have a relatively high initial hardness and high work hardening, compared with traditional alloys. The creep resistance of the HEA processed by HPT was determined by a nanoindentation technique. The strain rate sensitivity, m, increases with the decreasing of grain size, for smaller activation volume and the dominant deformation mechanism changing from the dislocation slip to grain-boundary slide. The present results give the plastic-deformation mechanism and mechanical properties evolution of single-phase HEA processed by HPT at room temperature. (C) 2015 Elsevier B.V. All rights reserved.