Microscopic strain localisation in Ti-6Al-4V during uniaxial tensile loading
Microscopic strain localisation in Ti-6Al-4V during uniaxial tensile loading
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DOI：
10.1016/j.msea.2016.10.099
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发表时间：
2017-01-05
期刊：
影响因子：
6.4
通讯作者：
Preuss, M.
中科院分区：
文献类型：
--
作者：
Lunt, D.;da Fonseca, J. Quinta;Preuss, M.
采用数字图像相关（DIC）和电子背散射衍射（EBSD）技术，通过局部应变测量与显微组织的相关性研究了Ti-6Al-4V钛合金显微组织中宏观区的影响。研究了Ti-6Al-4V合金的三种不同的产物形式，包括强织构、中等织构和无宏观区条件，重点研究了主要宏观区取向、宏观区尺寸和加载方向的影响。应变局部化的特点是在微观尺度上使用光学显微镜在原位单轴拉伸载荷和分析记录的图像，使用数字图像相关。无宏区材料和强宏区条件下加载平行的宏区表现出均匀的应变行为在弹性和塑性应变区。在45度和90度下加载的强（软取向）宏区条件都表现出在晶粒中的非均匀应变行为，其c轴取向垂直于加载方向，而中间（硬取向）宏区材料表现出非均匀应变行为时，大多数晶粒的c轴平行于加载方向。强宏区材料表现出直接的相关性宏区与他们的晶粒有利于棱柱形滑移和高应变区域时，在45加载到伸长方向。将高应变局部化区域与基底和棱柱滑移的施密德因子图相关联，表明在90度加载时基底滑移的可能性。
The titanium alloy Ti-6Al-4V is investigated in terms of the effect of macrozones within the microstructure through cross correlation of local strain measurements and microstructure, using digital image correlation (DIC) and electron backscatter diffraction (EBSD) techniques. Three different product forms of Ti-6Al-4V including strong-, intermediate- and a no-macrozone condition with a weak texture have been investigated focusing on the impact of the primary macrozone orientation, macrozone dimensions and loading direction. Strain localisation was characterised at the microscale using optical microscopy during in-situ uniaxial tensile loading and analysing the recorded images using digital image correlation. The no-macrozone material and the strong-macrozone condition loaded parallel to the macrozones exhibited homogeneous strain behaviour in both the elastic and plastic strain regions. The strong (soft-orientated) macrozone condition loaded at 45 degrees and 90 degrees both exhibited heterogeneous strain behaviour in grains with their c-axis oriented perpendicular to the loading direction, while the intermediate (hard-oriented) macrozone material exhibited heterogeneous strain behaviour when the majority of grains had their c-axis parallel to the loading direction. The strong-macrozone material showed a direct correlation between macrozones with their grains favourably oriented for prismatic slip and high strain regions when loaded at 45 to the elongation direction. Correlating a region of high strain localisation with Schmid factor maps for basal and prismatic slip, suggests a likelihood of basal slip when loading at 90 degrees.