Temperature and orientation effects on the deformation mechanisms of α-Fe micropillars

被引：50

作者：

Hagen, A. B. ^{[1
]}

Snartland, B. D. ^{[1
]}

Thaulow, C. ^{[1
]}

机构：

[1] Norwegian Univ Sci & Technol NTNU, Dept Engn Design & Mat, NO-7491 Trondheim, Norway

来源：

ACTA MATERIALIA | 2017年 / 129卷

关键词：

Temperature effect; Dislocations; Micro-scale plasticity; Bcc iron; Yield stress; CENTERED-CUBIC METALS; SCREW DISLOCATIONS; PLASTIC-DEFORMATION; CORE STRUCTURE; BCC-FE; COMPRESSION; SIZE; IRON; BEHAVIOR; TUNGSTEN;

D O I：

10.1016/j.actamat.2017.03.006

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

In-situ uniaxial compression tests on [010] and [011] alpha-Fe pillars have been conducted at room temperature and -75 degrees C to study the mechanical response with focus on temperature and orientation effect. All pillars exhibit larger yield stresses and hardening at 75 degrees C. We attribute this phenomenon to the non-planarity of screw dislocations in bcc crystals and the larger contribution of screw dislocations in governing the micro-scale plasticity at lower temperatures, similar to what is common for many bcc metals. We employ molecular dynamics to simulate the compression process to elucidate the underlying dislocation mechanisms. Nanopillars deformed on the [011] orientation deform via twinning at both temperatures, while the plastic deformation behavior for [010] pillars are governed by intense dislocation activity. In addition, [011] nanopillars withstand higher stresses before yielding, in agreement with the compression experimental results. TEM examinations are also reported and reveal that temperature clearly influence the residual dislocation structure. (C) 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

引用

页码：398 / 407

页数：10

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