等通道转角挤压Al-10Mg-4Si合金的组织与性能研究
Study on Microstructures and Mechanical Properties of Al-10Mg-4Si Alloy Processed by Equal Channel Angular Pressing
马 建， 梁 伟， 边丽萍， 陈克华
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作者单位：（太原理工大学 材料科学与工程学院，山西 太原 030024）
中文关键字：Al-Mg-Si合金； 等通道转角挤压； 晶粒细化
英文关键字：Al-Mg-Si alloy; equal channel angular pressing; refinement
中文摘要：在250 ℃下以Bc路径对Al-10Mg-4Si合金进行4道次和8道次的等通道转角挤压，以求达到改善合金组织和提高合金力学性能的目的。扫描电子显微镜(SEM)和透射电子显微镜(TEM)对挤压前后的微观组织分析表明：铸态合金基体晶粒比较粗大，第二相Mg2Si以粗大的汉字状或骨骼状分布于基体晶界处；经ECAP挤压后，基体晶粒得到细化，原粗大的汉字状Mg2Si被碎化为短棒状或多边形状颗粒，并呈一定的弥散分布。室温拉伸测试结果表明：ECAP 4道次挤压后，合金的抗拉强度和伸长率由铸态的166 MPa、 1.64%提高为322 MPa、 21.7 %；ECAP 8道次挤压后，合金的伸长率继续提高为24.7%，但抗拉强度下降到293 MPa。
英文摘要：The Al-10Mg-4Si alloy was pressed by ECAP through 4 and 8 passes at 250 ℃ in route Bc. The microstructures of the alloy before and after ECAP were investigated by scanning electron microscope (SEM) and transmission electron microscope (TEM). The mechanical properties at room temperature were measured by tension test. The experimental results show that the as-cast microstructure of the alloy is very coarse, with the large Chinese script or skeleton-shaped Mg2Si distributed along the grain boundary; through ECAP, the matrix grain is significantly refined. The initial coarse Chinese-script-shape Mg2Si is obviously broken into fine rod-shaped or polygonal particles and the distribution becomes more dispersed. The tensile strength and elongation of the alloy through ECAP 4 passes increase from 166 MPa and 1.64% in the as-cast alloy to 322 MPa and 21.7 %, respectively; through 8 passes ECAP, the elongation further increases to 24.7%, but the tensile strength decreases to 293 MPa.