摘要
为了改善高硅Mg-Si-Zn合金的性能,通过实验添加元素Sr、Zr,对Mg-Si-Zn合金进行单一和复合变质.分析了Mg 2Si初生相和共晶Mg 2Si的形貌与尺寸,研究了高硅Mg-4Si-4Zn合金的组织变化规律.结果表明:Sr可将Mg-4Si-4Zn合金中粗大的初生Mg 2Si枝晶变为规则的块状,树枝晶尺寸由长90~130μm,宽50~70μm变为对角线长度为20~50μm,复杂汉字状的共晶Mg 2Si变质为细小的棒状;Sr在凝固过程中通过在Mg 2Si表面占位来阻碍其生长,当Sr加入量超过0.75%后合金组织中出现Mg xSr ySi z相,使Sr变质效果下降.经过Zr-Sr复合变质,Mg-4Si-4Zn镁合金初生Mg 2Si相形貌由不规则状转变为对称的六边形状,具有尖锐棱角的初生相逐渐减少,当Zr添加量达到0.9%时,变质效果最好,Mg 2Si相最为圆整.
In order to improve the properties of high-silicon Mg-Si-Zn alloy,the single modification by Sr and the compound modification by Sr/Zr are carried out in this study.The change of microstructure and the modification effects of the high-silicon Mg-4Si-4Zn alloy are investigated by analyzing the morphology and size of primary Mg2Si phase and eutectic Mg2Si.The results show that the coarse primary phase of Mg2Si in the microstructure of the Mg-4Si-4Zn alloy is transformed into regular block crystal by the addition of Sr with the dendrite size changing from the length of 90~130μm and the width of 50~70μm to 20~50μm and the eutectic Mg2Si with the complex Chinese script morphology is modified into fine rod shape.During the solidified process,the Sr atoms occupation of the surface of Mg2Si crystals can suppress the growth of Mg2Si crystal.But there appears the MgxSrySiz phase in the solidified microstructure of the magnesium alloy when the Sr addition exceeds 0.75%,which brings the Sr modification effect decreasing.By the compound modification of Zr and Sr,the morphology of the Mg2Si primary phase in the microstructure of the Mg-4Si-4Zn magnesium alloy is changed from irregular shape to symmetrical hexagon shape with the Mg2Si primary phase with sharp edges and corners decreasing gradually.The best modification effect is realized when the Zr addition is reached to 0.9%,with the roundest Mg2Si phase.
作者
金东明
刘雨林
童文辉
黄博男
傅霄云
宋玮
王兴奇
Jin Dongming;Liu Yulin;Tong Wenhui;Huang Bonan;Fu Xiaoyun;Song Wei;Wang Xingqi(School of Materials Science and Engineering,Shenyang Aerospace University,Shenyang 110136,China)
出处
《材料与冶金学报》
CAS
北大核心
2020年第2期127-133,共7页
Journal of Materials and Metallurgy
基金
辽宁省教育厅资助项目(L2015410)
大学生创新创业训练计划(201810143036).
作者简介
金东明(1997-),男,硕士研究生;童文辉(1971-),男,副教授,E-mail:2407089517@qq.com.
