Cu-Sn-Bi合金在球磨和烧结过程中的组织演变

摘要

采用机械合金化法制备出Cu-10%Sn-5%Bi合金粉末,然后将其压制成型并进行烧结,制备成合金块体;利用X射线衍射(XRD)和扫描电镜(SEM)等分析手段,研究Cu-Sn-Bi合金在高能球磨和烧结过程中组织结构的变化.结果表明:高能球磨可以扩展Cu-Bi互不溶体系的固溶度,且在球磨过程中形成的Cu6Sn5相为亚稳定相,随着球磨时间延长会先形成而后发生分解,分解后的Sn将固溶到Cu中;同时在450 r/min球磨40 h后,Sn、Bi基本完全融入Cu中,形成Cu的过饱和固溶体.在烧结过程中,Bi从Cu中脱溶,细小弥散分布在Cu基体中.在700℃二次烧结后,Cu-Sn-Bi合金显微组织良好,具有相对较好的力学性能.%The mechanical alloying (MA) was used to prepare Cu-10%Sn-5%Bi alloy powders. Then the bulk alloy was obtained by a combination of cold pressing and conventional powder sintering. The microstructure evolutions of Cu-10%Sn-5%Bi alloy during ball milling and sintering were investigated by XRD and SEM. The results show that high-energy milling can extend solid solubility of Cu-Bi immiscible system, and the metastable Cu6Sn5phase successively happens to formation and decomposition with milling time. Meanwhile, the decomposition Sn is dissolved into Cu matrix. After milling with 450 r/min for 40 h, both Sn and Bi are completely dissolved into Cu matrix and a supersaturated solid solution of Cu(Sn, Bi) is formed. During sintering, Bi precipitates from Cu(Sn, Bi) supersaturated solid solution, are fine and dispersed homogeneously in Cu(Sn) matrix. The Cu-Sn-Bi alloy twice sintered at 700℃ exhibits an excellent microstructure and mechanical properties.