采用实验方法 ,确定了倒装焊 Sn Pb焊点的热循环寿命 .采用粘塑性和粘弹性材料模式描述了 Sn Pb焊料和底充胶的力学行为 ,用有限元方法模拟了 Sn Pb焊点在热循环条件下的应力应变过程 .基于计算的塑性应变范围和实验的热循环寿命 ,确定...采用实验方法 ,确定了倒装焊 Sn Pb焊点的热循环寿命 .采用粘塑性和粘弹性材料模式描述了 Sn Pb焊料和底充胶的力学行为 ,用有限元方法模拟了 Sn Pb焊点在热循环条件下的应力应变过程 .基于计算的塑性应变范围和实验的热循环寿命 ,确定了倒装焊 Sn Pb焊点热循环失效 Coffin- Manson经验方程的材料参数 .研究表明 ,有底充胶倒装焊 Sn Pb焊点的塑性应变范围比无底充胶时明显减小 ,热循环寿命可提高约 2 0倍 。展开更多
The effect of cryogenic temperatures on the mechanical properties and fracture mechanism of SnAgCu−SnPb mixed solder joints was investigated.The results showed that the tensile strength of mixed solder joints first in...The effect of cryogenic temperatures on the mechanical properties and fracture mechanism of SnAgCu−SnPb mixed solder joints was investigated.The results showed that the tensile strength of mixed solder joints first increased with the increase of Pb content and reached its maximum at 22.46 wt.%Pb;subsequently,it decreased as Pb content increased.However,cryogenic temperatures improved the tensile strength of the solder joints.Both Pb content and cryogenic temperature caused the fracture mode of the mixed solder joints to change;however,temperature remained the main influencing factor.As the temperature fell from 298 to 123 K,the failure pattern in the solder joints transformed from ductile fracture to quasi-ductile fracture to quasi-brittle fracture and finally,to brittle fracture.展开更多
文摘采用实验方法 ,确定了倒装焊 Sn Pb焊点的热循环寿命 .采用粘塑性和粘弹性材料模式描述了 Sn Pb焊料和底充胶的力学行为 ,用有限元方法模拟了 Sn Pb焊点在热循环条件下的应力应变过程 .基于计算的塑性应变范围和实验的热循环寿命 ,确定了倒装焊 Sn Pb焊点热循环失效 Coffin- Manson经验方程的材料参数 .研究表明 ,有底充胶倒装焊 Sn Pb焊点的塑性应变范围比无底充胶时明显减小 ,热循环寿命可提高约 2 0倍 。
基金The authors are grateful for the financial supports from the National Natural Science Foundation of China(No.51965044)the Aeronautical Science Foundation of China(No.20185456005).
文摘The effect of cryogenic temperatures on the mechanical properties and fracture mechanism of SnAgCu−SnPb mixed solder joints was investigated.The results showed that the tensile strength of mixed solder joints first increased with the increase of Pb content and reached its maximum at 22.46 wt.%Pb;subsequently,it decreased as Pb content increased.However,cryogenic temperatures improved the tensile strength of the solder joints.Both Pb content and cryogenic temperature caused the fracture mode of the mixed solder joints to change;however,temperature remained the main influencing factor.As the temperature fell from 298 to 123 K,the failure pattern in the solder joints transformed from ductile fracture to quasi-ductile fracture to quasi-brittle fracture and finally,to brittle fracture.
