New experimental insight into the mechanisms of nanoplasticity
New experimental insight into the mechanisms of nanoplasticity
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DOI：
10.1016/j.actamat.2013.08.032
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发表时间：
2013-11-01
期刊：
影响因子：
9.4
通讯作者：
Kurmanaeva, L.
中科院分区：
文献类型：
--
作者：
Skrotzki, W.;Eschke, A.;Kurmanaeva, L.
纳米Pd-10at.%的微结构和织构的演变采用X射线线轮廓分析和X射线微区衍射方法研究了Au合金（初始晶粒尺寸为16 nm）在室温下高压扭转（HPT）剧烈塑性变形后的组织。此外，显微硬度的变化进行测量和纹理建模。在HPT的微观结构的变化：微晶尺寸超过最大值，位错密度经历一个最小值和堆垛层错的密度降低/高达剪切应变类似于1，对应于20 nm的晶粒尺寸。从随机织构开始，典型的黄铜型剪切分量在类似于1的剪切应变以上发展。显微硬度随晶粒尺寸的减小在nm处出现最大值。显微组织，织构和强度的相关变化强烈建议从位错滑移的晶界滑动（GBS）为主的变形机制的过渡。未预料到的黄铜型织构及其偏离理想位置可以用泰勒模型模拟，假设占主导地位的部分位错滑移和GBS的一定贡献，分别。两者合计，许多技术应用于同一材料的结果，特别是那些纹理调查，提供了一个更全面和一致的图片比以前报道的面心立方金属的纳米塑性。(C)2013 Acta Materialia Inc.由Elsevier Ltd.出版。保留所有权利。
The evolution of microstructure and texture of a nanocrystalline Pd-10 at.% Au alloy (initial grain size 16 nm) subjected to severe plastic deformation by high-pressure torsion (HPT) at room temperature is investigated by X-ray line profile analysis and X-ray microdiffraction, respectively. In addition, changes in the microhardness are measured and the texture is modeled. During HPT the microstructure changes: the crystallite size goes over the maximum, the dislocation density goes through a minimum and the density of stacking faults decreases at/up to a shear strain of similar to 1, corresponding to a grain size of 20 nm. Starting with a random texture, typical brass-type shear components develop at a shear strain above similar to 1. The microhardness with decreasing crystallite size goes over a maximum at nm. The correlated changes in microstructure, texture and strength strongly suggest the transition from a dislocation slip to a grain boundary sliding (GBS)-dominated deformation mechanism. The unexpected brass-type texture and its deviation from the ideal position can be simulated with the Taylor model assuming dominant partial dislocation slip and a certain contribution of GBS, respectively. Taken together, the results of many techniques applied to the same material, in particular those of the texture investigations, provide a more comprehensive and consistent picture of nanoplasticity than reported before for face-centered cubic metals. (C) 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.