强制冷却搅拌摩擦加工2024铝合金晶粒特征

发布时间：2018-11-28 15:51

【摘要】：在强制冷却环境下,对2024铝合金进行了搅拌摩擦加工,并采用电子背散射衍射技术对加工后各区域的晶粒特征及演化进行了研究。结果表明,从母材区、热机影响区到搅拌区,晶粒尺寸逐渐减小,搅拌区组织明显细化,且分布均匀,平均晶粒尺寸为1.89μm。母材区大角度晶界居多,而热机影响区小角度晶界居多,搅拌区取向差分布呈现双峰现象。母材区为{124}211R取向,热机影响区主要为{001}110R-cube取向,搅拌区表现出较强的{113}110取向,热机影响区晶粒取向与搅拌区晶粒取向相近,表明在低温高应变条件下连续动态再结晶是搅拌区晶粒细化的主要机制。拉伸试样的断裂位置位于热机影响区,这与{001}110R-cube取向的可动滑移系数量和滑移难易程度一致。
[Abstract]:Friction stir processing of 2024 aluminum alloy was carried out in forced cooling environment. The grain characteristics and evolution of each region after processing were studied by electron backscatter diffraction (EBSD) technique. The results show that from the base metal area to the stirring zone, the grain size decreases gradually, and the microstructure of the stirring zone is finer and more evenly distributed, with an average grain size of 1.89 渭 m. The large angle grain boundary is more in the base metal area, and the small angle grain boundary is the majority in the heat engine affected area. The distribution of orientation difference in the mixing zone is double peak phenomenon. The base metal region is {124} 211R orientation, and the heat engine effect zone is mainly {001} 110R-cube orientation. The agitation region shows a strong {113} 110orientation, and the grain orientation of the heat-mechanically affected region is similar to that of the agitated region. It is shown that continuous dynamic recrystallization is the main mechanism of grain refinement in agitated region under low temperature and high strain conditions. The fracture position of tensile specimen is located in the zone affected by heat engine, which is consistent with the number of movable slip systems and the ease of sliding of {001} 110R-cube orientation.
【作者单位】：西安建筑科技大学;中冶东方工程技术有限公司;
【基金】：国家自然科学基金(51074119,51274161,51404180) 陕西省工业攻关项目(2013K09-11) 西北工业大学凝固技术国家重点实验室项目基金(SKLSP201009)
【分类号】：TG146.21

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