等温热处理对消失模铸造AZ91D镁合金组织与性能的影响  

Effects of isothermal heat treatment on microstructure and mechanical properties of lost foam casting AZ91D magnesium alloy

作　　者：李继强[1] 樊自田[1] 王元庆[1] 董选普[1] 

机构地区：[1]华中科技大学材料成型及模具技术国家重点实验室,湖北武汉430074

出　　处：《金属热处理》2008年第1期97-100,共4页Heat Treatment of Metals

基　　金：国家自然科学基金项目(50275058);国家高技术研究发展计划(863)项目(2007AA03Z113)

摘　　要：对AZ91D镁合金消失模铸件进行了近半固态等温热处理,通过光学显微镜、扫描电镜以及金属拉伸试验对其组织和力学性能进行了研究。结果表明,AZ91D镁合金消失模铸件经过530℃×60 min近半固态等温热处理后,合金显微组织中β-Mg17A l12相基本熔入基体,枝晶状的铸态组织在等温处理过程中变得均匀圆整,由此产生的固溶强化作用使材料的力学性能大大提高,抗拉强度达到213.17 MPa,屈服强度达到115.63 MPa,伸长率达到4.11%,等温热处理后的断口呈现明显的韧性断裂特征。The microstructures and mechanical properties of AZ91D magnesium alloy by lost foam casting （LFC） were investigated by OM,SEM and tensile test after closing semi-solid isothermal heat treatment. The results show that when the AZ91D magnesium alloy parts are treated by closing semi-solid isothermal heat treatment at 530 ℃ for holding 60 min,the β-Mg17 Al12-phase basically solutionizes in matrix and dendrites as-cast gradually evolves into fine spheroid shape during the holding. The mechanical properties of the alloy are significantly improved after the heat treatment. The tensile strength, yield strength and elongation achieve 213.17 MPa, 115. 63 MPa, and 4. 11%, respectively. The tensile fractographs after the treatment present the obvious gliding fracture characteristics.

关 键 词：AZ91D镁合金 近半固态 等温热处理 组织演变 

分 类 号：TG156[金属学及工艺—热处理] TG162.4[金属学及工艺—金属学]