The microstructure and microtexture evolution at the outside of the cross-section of AZ31 magnesium alloy profile before and after warm bending were investigated by using optical microscope, X-rays diflractometer and electron back scattering diffraction (EBSD) analysis system. The results indicate that the microtexture of the profile before bending is line texture with (KHO) parallel to the extrusion direction. The intensity of line texture of the profile after bending is reduced. During the warm bending process, the amount on the extension twins decrease from 5.39% to 2.22%. Whereas, the amount of the compression twins increases from 0.141% to 0.222%. Under condition of the stress concentration caused by lots of extension twins and the effect of temperature, the non-basal slip systems are activated which coordinate the deformation of the c-axis. As a result, the plastic property of profile is improved.%采用光学显微镜、X射线衍射仪和EBSD分析研究AZ31镁合金型材温热弯曲成形前后横截面外侧微观组织和织构的演变规律.结果表明:弯曲成形前,型材为〈10(1)0〉平行于挤压方向的线织构；弯曲成形后,型材线织构被削弱.弯曲过程中拉伸孪晶数量减少,由弯曲前的5.39％降低至弯曲后的2.22％;压缩孪晶增多,由弯曲前的0.141％增加至弯曲后的0.222％.挤压型材的大量拉伸孪晶使得应力集中,协同温度的影响,非基面滑移开动并协调了晶粒c轴的应变,因而提高型材的塑性变形能力.
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