挤压铸造Mg-Zn-Y合金显微组织与力学性能的研究  

Study on Microstructure and Mechanical Properties of Mg-Zn-Y Alloy Prepared by Squeeze Casting

作　　者：吴金珂 侯华[1] 赵宇宏[1] 杨玲[1] 程书建 王冰[1] 

机构地区：[1]中北大学材料科学与工程学院,山西太原030051

出　　处：《铸造》2015年第12期1258-1263,共6页Foundry

基　　金：科技部国际科技合作项目(2014DFA50320);国家自然科学基金(51204147;51274175);山西省国际科技合作项目(20130810172012081013);山西省研究生教育创新项目(2015SY51)

摘　　要：采用光学显微镜(OM)、扫描电子显微镜(SEM)、X射线衍射(XRD)、万能拉伸试验机等手段,研究了不同挤压压力(0,50,100,150 MPa)对挤压铸造Mg_(93)Zn_6Y_1合金显微组织与力学性能的影响。结果表明:不同挤压压力下合金显微组织由基体α-Mg相和I-Mg_3YZn_6准晶相组成。α-Mg相呈枝晶状形态存在,分枝明显,I-Mg_3YZn_6准晶相以(I-Mg_3YZn_6+α-Mg)层片状共晶组织形态存在,呈网状分布在基体枝晶间。随着挤压压力的增大,α-Mg晶粒明显细化,层片状共晶组织变得细小,且由连续网状逐渐变为断裂网状,分布更均匀。合金的拉伸力学性能随着挤压压力的增大而逐渐提高,当挤压压力为150 MPa时,合金拉伸力学性能最优,其抗拉强度和伸长率分别为193 MPa和4.2%,增幅为30.4%和75.0%,合金力学性能的提高主要归因于细晶强化和I-Mg3YZn6相的强化作用。合金拉伸试样的断口形貌呈现准解理断裂特征。The effect of different applied pressures on microstructure and mechanical properties of squeeze cast Mg-Zn-Y alloy was investigated by optical microscopy （OM）, scanning electron microscopy （SEM）, X-ray diffraction（XRD）, and tensile testing. The results show that microstructure of Mg93Zn6Y1 alloy under different applied pressures consist of α-Mg and lamellar （α-Mg＋I-Mg3YZn6） eutectic phase distributed between α-Mg dendrite. With the applied pressure increase, the α-Mg grain size obviously refines and the layer of eutectic organization become smaller, the eutectic changes from continuous mesh into the fracture network and dispersive distribution. The mechanical properties of the alloy increase gradually with increasing the applied pressure change from 0 to 150 MPa. When the applied pressure is 150 MPa, the ultimate tensile strength and elongation to failure are 193 MPa and 4.2%, respectively, which are 30.4% and 75.0% higher than the corresponding values of the samples prepared without applied pressure. The improvements of the tensile properties of alloy were ascribed to the grain boundary strengthening by grain refinement and strengthening by I-Mg3YZn6 phase. The fracture morphology of Mg-Zn-Y fracture. alloys shows the characteristic of quasi-cleavage

关 键 词：挤压铸造 Mg93Zn6Y 合金 显微组织 力学性能 

分 类 号：TG292[金属学及工艺—铸造] TG146.22[一般工业技术—材料科学与工程]