机械合金化制备Ag-Cu-Sn钎料的组织和热稳定性

研究了机械合金化制备Ag-Cu-Sn三元体系形成过饱和固溶体的可能性,并对所得到的非平衡球磨产物的组织结构、热稳定性及其铺展重熔后的金相组织进行了表征。结果表明,通过控制球磨工艺和第三组元含量,可得到以过饱和固溶体为主要组成相的钎料合金粉,减少或细化脆性金属间化合物相。真空退火时,富银固溶体相较稳定,富铜固溶体相易于分解生成Cu_3Sn,银锡化合物可分解形成Ag基固溶体和富锡相,铜锡化合物的分解产物则为多种中间相,随退火温度的升高,转变顺序逐渐向铜锡原子比例增大的方向进行。以过饱和固溶体为主要组成相的钎料合金粉在重熔后虽然仍存在金属间化合物相,但金相组织明显细化。

Investigation of Microstructure and Thermo-stability of Ag-cu-sn Filler Metal Powders Prepared by Mechanical Alloying

Ag-Cu-Sn filler alloy was synthesized by the mechanical alloying method in order to get the supersaturated solid solution phase instead of brittle intermetallics to avoid the embrittlement of the joint.Microstructure and thermo-stability of the Ag-Cu-Sn final milling products were investigated.Results indicated that the mixture of Ag (Cu,Sn) and Ag (Cu) solid solution phases could be obtained by controlling the ball milling time and the tin content.During the vacuum annealing,Ag-rich solid solution was stable while Cu-rich solid solution was easy to decompose and transformed into Cu3Sn intermetallic compound.Meanwhile Ag-Sn compound could be decomposed to Ag-based solid solution and Sn-rich phase.The decomposition products of Cu-Sn compound were a variety of mesophases.Cu/Sn ratio increased with the increasing of the annealing temperature.After the remelting test,the refined microstructure was formed,which should be beneficial to the bonding strength after brazing.