Nd对过共晶Al-18Mg_2Si合金组织、力学性能及变形行为的影响  

Influence of Nd Addition on Microstructure,Tensile Properties, and Fracture Behavior of Cast Al-18Mg_2Si Alloy

作　　者：武晓峰[1] 王喆[1] 

机构地区：[1]辽宁工业大学材料科学与工程学院,辽宁锦州121001

出　　处：《辽宁工业大学学报（自然科学版）》2012年第4期241-246,共6页Journal of Liaoning University of Technology(Natural Science Edition)

摘　　要：采用Nd对过共晶Al-18Mg2Si合金进行变质处理;利用金相显微镜等观察了变质前后合金的微观组织;测试了合金的拉伸性能;并对变质前后合金的断口形貌、变形行为进行了分析。结果表明:在过共晶Al-18Mg2Si合金中添加适量的Nd对初生和共晶Mg2Si能够同时起到良好的变质作用,初生Mg2Si的形貌由粗大的树枝状或多角形块状转变为细小的块状,而共晶Mg2Si则由粗大的片状转变为细小的片状、纤维状。经0.5%Nd变质后,材料的拉伸性能得到大幅度提高,抗拉强度和伸长率分别提高了32.4%和200%.同时,Nd的添加使合金的断口出现了韧性断裂的特征。Nd was adopted to modify hypereutectic Al-18 Mg2Si alloy. The microstructures before and after modification were examined by OM, tensile properties were measured, and the fracture morphologies were analyzed by SEM before and after modification. Experimental results expatiate that, after introducing a proper amount of Nd, both primary and euteetie Mg2Si in the Al-18 wt.%Mg2Si alloy are well modified. The morphology of primary Mg2Si is changed from irregular or dendritic to polyhedral shape, and its average particle size significantly decreases from 47.5 to 13.0 ttrn. Moreover, the morphology of the eutectie Mg2Si phase is altered from flake-like to a thin laminar, short fibrous or dot-like structure. Tensile tests reveal that Nd addition improves the tensile strength and ductility of the material. Compared with those of unmodified alloy, the ultimate tensile strength and percentage elongation with 0.5% Nd are increased by 32.4% and 200%, respectively. At the same time, ductile characteristic appears after adding Nd.

关 键 词：过共晶Al-Mg2Si合金 ND 变质 初生和共晶Mg2Si 力学性能 

分 类 号：TG111[金属学及工艺—物理冶金]