Work hardening and inherent plastic instability of nanocrystalline metals
Work hardening and inherent plastic instability of nanocrystalline metals
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纳米晶金属的加工硬化和固有的塑性不稳定性
DOI：
10.1002/pssr.201004095
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发表时间：
2010
期刊：
影响因子：
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通讯作者：
J. Weissmüller
中科院分区：
文献类型：
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作者：
L. Kurmanaeva;Yu. Ivanisenko;J. Markmann;K. Yang;H.-J. Fecht;J. Weissmüller
本文报道了纳米晶Pd和Pd_（90）Au_（10）（平均晶粒尺寸约为14 nm）的力学行为。所有试样在拉伸和压缩韧性脆性。我们分析了控制材料拉伸延展性潜力的参数，即应变硬化指数n和应变速率敏感性m。结果显示数值较低，n = 0.05。已知这种本构行为促进塑性不稳定性，并因此促进拉伸下的快速断裂。因此，我们的研究结果表明，局部变形的趋势是一个固有的功能，数控材料。看来nc材料在拉伸状态下的有限延展性与微观结构缺陷无关，而是nandm值较低的结果。（© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA，魏因海姆）
We report an investigation of the mechanical behaviour of nanocrystalline (nc) Pd and Pd90Au10with mean grain size around 14 nm. All specimens were brittle in tension and ductile in compression. We analyze the parameters that control a material's potential for ductility in tension, namely strain hardening exponent,n, and strain rate sensitivity,m. The results reveal low values,n≈m≈ 0.05. This constitutive behavior is known to promote plastic instability and, hence, rapid fracture in tension. Therefore, our results suggest that a tendency for localized deformation is an inherent feature of nc materials. It appears that the limited ductility of nc materials in tension is not related to microstructural flaws, but is a consequence of the concomitant low values ofnandm. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)