EBSD studies of the stress-induced B2-B19′ martensitic transformation in NiTi tubes under uniaxial tension and compression
EBSD studies of the stress-induced B2-B19′ martensitic transformation in NiTi tubes under uniaxial tension and compression
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DOI：
10.1016/j.actamat.2010.02.009
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发表时间：
2010-05-01
期刊：
影响因子：
9.4
通讯作者：
Han, X. D.
中科院分区：
文献类型：
--
作者：
Mao, S. C.;Luo, J. F.;Han, X. D.
对多晶NiTi管材拉伸和压缩变形过程中的电子背散射衍射（EBSD）进行了原位研究。拉伸下的长程协同和催化马氏体相变导致相变以螺旋Luders带的形式进行。谱带的传播与单个晶粒取向的空间分布密切相关。在单轴压缩中，施密德因子的较大变化，以及因此晶粒之间的临界相变应力的较大变化，导致均匀的马氏体相变，并且因此不存在Luders带。为了解释所观察到的拉压不对称性，提出了拉伸和压缩下多晶NiTi的临界相变应力和相变应变的晶体学模型。该模型定义了三个结晶区域：张力有利区，压缩有利区和中性区。拉伸应变大于压缩应变的取向布居远高于具有较高压缩应变的取向。对于分解的剪切应力，有利于拉伸和压缩的取向布居没有表现出任何大的差异。(C)2010 Acta Materialia Inc.由爱思唯尔有限公司出版。保留所有权利。
In situ electron backscattering diffraction (EBSD) investigations were conducted on polycrystalline NiTi tube specimens during tensile and compressive deformation. The long-range cooperative and catalytic martensitic transformation under tension induces the transformation to proceed in the form of helical Luders band. Propagation of the band is closely related to the spatial distribution of the orientations of individual grains. In uniaxial compression, the larger variation in Schmid factors, and consequently the larger variation in the critical transformation stresses among grains, leads to a homogeneous martensitic transformation, and therefore the absence of the Luders band. To interpret the observed tension compression asymmetry, a crystallographic model of the critical transformation stress and transformation strain for polycrystalline NiTi under tension and compression is proposed. The model defines three crystallographic regions: tension-favorable, compression-favorable and neutral zones. The orientation population in which tensile strains are larger than compressive strains is much higher than that of orientations with higher compressive strains. For resolved shear stress, orientation populations favoring tension and compression do not show any great difference. (C) 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.