电阻法测量无铅焊点蠕变的有效性实验研究

Effectiveness experimental study on resistance test method for measuring creep of lead-free solder joints

为了解用于焊点性能评估的电阻测试法能否精确反映其蠕变特性，利用特制的焊点测试系统，同步采集无铅焊点在室温、25N载荷下的电阻应变和剪切蠕变。实验表明它们的总体变化趋势相似，均可分为线性与指数阶段，但变化速率存在明显差异。两者临界拐点的延时程度与焊点的尺寸因子k有关，在一定的范围内（k=4．5-8．5），延时程度仅在零值附近（±0.075）微小波动。故电阻法测量无铅焊点的蠕变是有效的，较好地反映了其蠕变损伤。

In order to research whether resistance test method which was used to evaluate the property of lead-free solder joints could accurately reflect the creep properties, the resistance strain and the shear creep （room temperature and 25 N load）of lead-free solder joints were collected synchronously by the specially-made test system. The experiments show that their change trends are similar, for both can be divided into linear phase and index phase, but the rates of change are different broadly. The time delay of their critical inflection points is related with the size factor k of the solder joints, the time delay fluctuate slightly near the zero value （±0.075） when k is in 4.5-8.5. So resistance test method is effective to measure the creep of lead-free solder joints, reflecting the creep damage preferably.