This work presents an experimental and numerical investigation of liquid-assisted healing with respect to solder joint composition and size. A damage-healing model is formulated based on entropy generation of damage and viscous material transport during healing. The model accounts for a composition-dependency of healing by introducing the liquid film thickness, the liquid viscosity and a microstructural mobility parameter. The size dependencies enter the healing model in form of the local capillary pressure of the solder joint. A viscous flow experiment illustrates the compositional dependency of local material transport and a cyclic tensile experiment shows the regain of mechanical properties, such as, stiffness and strength after healing. The flow experiment shows that material transport is retarded for solders of low liquid fraction and crack healing is limited due to partial filling of the crack. Simulation results of a solder array suggest the capillary pressure as the driving force for healing, which leads to a size-dependency of the healing evolution. The required time for complete healing increases with reduced solder dimensions due to higher capillary pressures. Microstructural mobility due to high liquid fractions also promotes healing.

这项工作提出了关于焊缝成分和尺寸的液体辅助修复的实验和数值研究。基于修复过程中损伤的熵产生和粘性物质的运输，建立了损伤修复模型。该模型通过引入液膜厚度，液体粘度和微结构迁移率参数来说明愈合的成分依赖性。尺寸相关性以焊点的局部毛细压力的形式进入修复模型。粘性流动实验说明了局部材料传输的成分依赖性，而循环拉伸实验表明了恢复后的机械性能（如刚度和强度）的恢复。流动实验表明，对于液体含量低的焊料，材料的传输受到阻碍，并且由于裂纹的部分填充，裂纹的愈合受到限制。焊料阵列的仿真结果表明，毛细管压力是治愈的驱动力，这导致了愈合过程的大小依赖性。由于较高的毛细管压力，随着焊料尺寸的减小，完成完全修复所需的时间也会增加。由于高液体分数导致的微结构流动性也促进了愈合。