Mixed rare earth metals,which were composed of La powder and Nd powder,was added into Zn9.3Al7Cu alloy solder with mass fractions of 0,0.1%,0.3%,0.5%,respectively.The effects of mixed rare earth content on the melting point,wettability,microstructure,and on the shear strength of Cu/Al solder joint were studied.The results show that the microstructures of the alloy solders consisted ofη(Zn)phase,ε(CuZn5 )phase,β(ZnAl)eutectoid phase.The addition of the mixed rare earth resulted in the refinement and evenly distribution of the large dendriticε(CuZn5 )phase.With increasing content of mixed rare earth,the melting points of the alloy solders decreased while the wettability of the solder and the shear strength of the Cu/Al solder joint first increased and then decreased.When the mass fraction of the mixed rare earth was 0.1%,the spread areas of the solder on Al and Cu plates reached the maximum values,which were 20.4% and 46.6% higher than those without rare earth, respectively;the interface between the wetted Al plate by the solder became continuous without defects;the shear strength of Cu/Al joint welded with the alloy solder reached the maximum value of 66.5 MPa,which was 32.5%higher than that without rare earth.%在Zn9.3Al7Cu合金钎料中添加了质量分数分别为0,0.1%,0.3%,0.5%的由镧粉和钕粉组成的混合稀土,研究了混合稀土含量对该合金钎料熔点、润湿性能、显微组织,以及对其钎焊铜/铝接头剪切强度的影响.结果表明:合金钎料的显微组织均由η(Zn)相、ε(CuZn5)相、β(ZnAl)共析相组成,混合稀土的添加使大树枝状的ε(CuZn5)相细化、分布变均匀;随着混合稀土含量的增加,合金钎料的熔点逐渐降低,润湿性能及其钎焊铜/铝接头的剪切强度均先增大后下降;当混合稀土质量分数为0.1%时,钎料在铜板和铝板上的铺展面积均达到最大,分别比未添加稀土的提高了20.4%和46.6%,其润湿铝板的界面变得连续,没有缺陷;合金钎料钎焊铜/铝接头的剪切强度也达到最大,为66.5 MPa,比未添加稀土的提高了32.5%.
展开▼
