热挤压对15%Mg2Si/Al-Si-Cu复合材料组织及性能的影响  

Effect of hot extrusion on microstructure and properties of 15% Mg_(2)Si/Al-Si-Cu composites

作　　者：刘丹丹 郭学锋[1,2] 杨文朋 LIU Dan-dan;GUO Xue-feng;YANG Wen-peng(School of Materials Science and Engineering,Henan Polytechnic University,Jiaozuo 454000,China;Henan International Joint Research Laboratory for High-Performance Light Metallic Materials and Numerical Simulations,Jiaozuo 454000,China)

机构地区：[1]河南理工大学材料科学与工程学院,河南焦作454000 [2]河南省高性能轻金属材料及数值模拟国际联合实验室,河南焦作454000

出　　处：《材料热处理学报》2021年第4期17-24,共8页Transactions of Materials and Heat Treatment

基　　金：国家自然科学基金(51571086,51271073);河南理工大学自然科学基金(B2010-20)。

摘　　要：采用熔炼法制备了15%Mg_(2)Si/Al-3%Cu-3%Si复合材料,并研究了热挤压对复合材料的组织及性能的影响。结果表明,铸态15%Mg_(2)Si/Al-Cu-Si复合材料中初生Mg_(2)Si相(记为Mg_(2)Si_(p))呈多边形状,且大都具有尖锐的棱角,其尺寸(D_(Mg_(2)Si_(p)))约为31.24μm,菊花状的共晶Mg_(2)Si相(记为Mg_(2)Si_(e))偏聚在Mg_(2)Si_(p)周围,Al_(2)Cu相呈不规则的网状。经过460℃固溶处理6 h后,Al_(2)Cu相明显减少,Mg_(2)Si_(e)部分固溶到基体中,部分与Al、Cu元素结合,形成Al_(4)Cu_(2)Mg_(8)Si_(7)四元Q相。经过往复挤压1道次后,Mg_(2)Si_(p)明显破碎,沿挤压流线方向分布,且边缘区域的破碎效果比中心区域更为显著。经过往复挤压1道次和正挤压后,Mg_(2)Si_(p)分布均匀,尺寸最小,约为12.89μm,与铸态相比减小了58.7%。随着挤压道次的增加,复合材料组织中的Al_(3)Cu_(2)Mg_(9)Si_(7)相(Q_(1)相)逐渐被破碎细化,同时在挤压过程中沿挤压流线析出细小弥散的Al_(4)CuMg_(5)Si_(4)相(Q_(2)相)。对热挤压后的复合材料进行三点抗弯测试,结果表明,复合材料的强度和塑性大幅度提高。其中,经过往复挤压3道次和正挤压后复合材料的强度和应变分别为306 MPa和6.72%,与铸态相比分别提高了23.9%和482.3%,塑性得到了很大的提高。15%Mg_(2)Si/Al-3%Cu-3%Si composites were prepared by melting method,and effect of hot extrusion on microstructure and properties of the 15%Mg_(2)Si/Al-Si-Cu composites was studied.The results show that the primary Mg_(2)Si phase(Mg_(2)Si_(p))of the as-cast 15%Mg_(2)Si/Al-3%Cu-3%Si composites is in a polygonal shape,most have sharp corners,and the size is about 31.24μm.The chrysanthemum-shaped eutectic Mg_(2)Si phase(Mg_(2)Si_(e))is clustered around the primary Mg_(2)Si_(p)phase,and the Al_(2)Cu phase is in irregular network shape.After solid solution treatment at 460℃for 6 h,the amount of Al_(2)Cu phase is significantly reduced,part of Mg_(2)Sie phase is dissolved into the matrix and partially reacts with Al and Cu elements to form Al_(4)Cu_(2)Mg_(8)Si_(7)quaternary phase(Q).After reciprocating extrusion(REX)for one pass,the Mg_(2)Si_(p)phase is significantly broken and distributed along the direction of extrusion streamline,and the breaking effect in the edge area is more significant than that in the central area.After reciprocating extrusion(REX)for one pass and forward extrusion(FEX),the Mg_(2)Si_(p)phase distribution is uniform and the size is the smallest,about 12.89μm,which is reduced by 58.7%compared with the as-cast composites.With the increase of reciprocating extrusion pass,the Al_(3)Cu_(2)Mg_(9)Si_(7)phase(Q_(1) phase)of the composites is gradually broken and refined,and the fine dispersed Al_(4)CuMg_(5)Si_(4) phase(Q_(2) phase)is precipitated along the extrusion streamline during the extrusion.The results of three-point bending test show that the strength and plasticity of the hot extruded composites are greatly improved,and the strength and strain of the composites after REX for 3 passes and FEX are 306 MPa and 6.72%,respectively,which is 23.9%and 482.3%higher than that of the as-cast composites,indicating that the plasticity of the composites is greatly improved.

关 键 词：15%Mg_(2)Si/Al-3%Cu-3%Si复合材料 热挤压 显微组织 力学性能 

分 类 号：TG331[金属学及工艺—金属压力加工]