细间距器件焊点力学性能与数值模拟

采用再流焊方法对细间距器件进行钎焊试验，针对使用SnAgCu和SnPb两种钎料对应的焊点进行了研究。结果表明，SnAgCu焊点的拉力明显高于SnPb焊点，说明SnAgCu对应焊点的抗拉强度更高。对焊点断口组织分析发现，SaAgCu焊点拉伸断裂方式为韧性断裂，而SnPb焊点的断裂方式兼有脆性断裂和韧性断裂的特征。运用非线性有限元模拟，针对焊点在温度循环载荷作用下的力学性能分析，发现SnAgCu焊点的应力应变以及非线性应变能明显小于SnPb焊点对应的数值。说明SnAgCu焊点的可靠性明显高于SnPb焊点。模拟结果和试验研究结果吻合，该研究为无铅钎料的进一步研究提供理论指导。

Study on mechanical properties and numerical simulation of fine pitch devices soldered joints

Soldering experiments of fine pitch devices were carried out using IR reflow soldering method for SnAgCu and SnPb soldered joints.The results show that the tensile force of SnAgCu soldered joints is higher than that of SnPb soldered joints.By analyzing the fracture microstructure of soldered joints, it is found that the fracture mechanism of SnAgCu soldered joints is due to toughness fracture, while fracture mechanism of SnPb soldered joints includes brittle fracture and toughness fracture.Through finite element simulation, the aralytical results indicate the value of strain, stress and nonlinear strain energy of SnAgCu soldered joints are lower than those of SnPb soldered joints under temperature cyclic loading, which means the reliability of SnAgCu soldered joints is higher than SnPb soldered joints.The results of simulation accord with the experiments, which would provide a reference for theoretical investigation of lead-free solders.