【摘要】 在Sn-3.0Ag-0.5Cu（SAC305）焊料中熔入0.5%～10%（质量分数）的In粉以改变钎料的显微组织，进而改善焊料的性能。实验结果表明：β-Sn（In）、Ag₃（Sn,In）和Cu₆（Sn,In）₅相存在于所有的含In钎料中，在SAC305-10In焊料中发现了InSn₄物相。随着In含量的增加，β-Sn晶粒形核点增加，其形核模型由{101}转变为{301}，从而细化β-Sn晶粒，使得β-Sn的形态由粗大晶粒转变为交错晶粒，最后转变为多晶粒。结果表明，这种β-Sn晶粒形态转变引起细晶强化与固溶强化的联合作用，使得SAC305-xIn焊料的显微硬度随着In添加量的增加而显著升高。更多还原

【Abstract】 In powders with different contents（0.5-10 wt.%） were melted into the Sn-3.0Ag-0.5Cu（SAC305） solder to change the microstructure and thus improve the properties of the solder. The results showed that β-Sn（In）, Ag₃（Sn,In） and Cu₆（Sn,In）₅ phases existed in all the In-added solders, and an additional phase of InSn₄ was found in the SAC305-10In solder. With increasing In addition amount, the β-Sn nucleation sites were increased and the nucleation model was changed from {101} to {301}, which refined the β-Sn grains and transformed the β-Sn morphology from large grains to interlaced grains and finally to multiple grains. As a result, a combined effect of fine grain strengthening and solid solution strengthening was achieved to increase the microhardness of the SAC305-x In solders with increasing In addition amount.更多还原