Enhanced strain rate sensitivity of Zr-based bulk metallic glasses subjected to high pressure torsion
Enhanced strain rate sensitivity of Zr-based bulk metallic glasses subjected to high pressure torsion
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DOI：
10.1016/j.jallcom.2018.03.018
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发表时间：
2018-05-30
影响因子：
6.2
通讯作者：
Valiev, R. Z.
中科院分区：
文献类型：
--
作者：
Boltynjuk, E. V.;Gunderov, D. V.;Valiev, R. Z.
在室温下对Zr 62 Cu 22 Al 10 Fe 5Dy 1大块非晶合金进行了高压扭转实验。HPT处理后的状态表明在非晶结构中存在大量的非均匀性-剪切带。采用纳米压痕法研究了HPT处理对变形行为和应变速率敏感性（m）的影响。结果发现，HPT显着影响力学行为的BMG在纳米压痕。HPT后硬度和杨氏模量降低。同时，HPT处理导致m从铸态材料的0.014增加到0.036。除上述变化外，压痕周围无锯齿流和剪切带。一个更少的局部化变形模式下纳米压痕沿着与HPT处理状态的应变速率敏感性的值相比，初始状态的增加意味着均匀的变形行为后处理。所观察到的变形行为和结构的急剧变化可以解释为HPT处理的结果中类似于纳米玻璃的高度异质的非晶结构的形成。(C)2018 Elsevier B. V.版权所有。
The Zr62Cu22Al10Fe5Dy1 bulk metallic glass (BMG) was subjected to high pressure torsion (HPT) at room temperature. The state after HPT processing demonstrates presence of large number of heterogeneities in amorphous structure - shear bands. Nanoindentation was used to study the effect of HPT processing on deformation behavior and strain rate sensitivity (m). It was found that HPT significantly affects mechanical behavior of BMG during nanoindentation. Decrease in hardness and Young's modulus was observed after HPT. At the same time HPT processing led to an increase in m from 0.014 for the as-cast material to 0.036. The lack of serration flow and shear bands around imprints was observed in addition to above mentioned changes. A much less localized deformation mode under nanoindentation along with an increase in values of strain rate sensitivity of HPT-processed state in comparison with the initial state imply homogeneous deformation behavior after processing. The observed drastic changes in deformation behavior and structure can be explained as the formation of a highly-heterogeneous amorphous structure resembling nanoglasses in result of HPT processing. (C) 2018 Elsevier B.V. All rights reserved.