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通过金相显微镜、扫描电镜、透射电镜以及抗蠕变试验机等,研究Sn2.5Ag0.7Cu_xRE钎料合金以及钎焊接头的组织和高温蠕变行为。结果表明,Sn2.5Ag0.7Cu合金组织由富Sn基体相及共晶相构成。共晶相包含二元共晶相β-(Sn)+Cu_6Sn_5、Ag_3Sn+β-(Sn)和三元共晶相β-(Sn)+Ag_3Sn+Cu_6Sn_5。随着稀土含量的增加,合金组织细化作用显著,界面IMC的厚度降低,IMC由尺寸较大的扇贝状转变为波浪状。同时,合金蠕变断裂寿命不断增高,最高可以超过100 h,合金的晶界越来越明显,没有再结晶现象。
The microstructure and creep behavior of Sn2.5Ag0.7Cu_xRE solder alloy and brazed joints were studied by means of optical microscope, scanning electron microscopy, transmission electron microscopy and creep tester. The results show that Sn2.5Ag0.7Cu alloy consists of Sn-rich matrix and eutectic phases. The eutectic phase contains the binary eutectic phases β- (Sn) + Cu_6Sn_5, Ag_3Sn + β- (Sn) and the ternary eutectic phase β- (Sn) + Ag_3Sn + Cu_6Sn_5. With the increase of RE content, the effect of refinement of alloy is significant, the thickness of IMC decreases, and the IMC changes from a scalloped shape with larger size to a wavy shape. At the same time, the creep rupture life of the alloy is continuously increasing up to 100 h, the grain boundary of the alloy is more and more obvious, and there is no recrystallization.