外能辅助作用下的Cu/Sn2.5Ag0.7Cu0.1RE/Cu钎焊接头的时效断裂机制

Aging Fracture Mechanism of Cu/Sn2.5Ag0.7Cu0.1RE/Cu Brazed Joints Under External Energy Assist

在超声振动和电场辅助作用下进行了SnAgCuRE系钎料的钎焊试验。为模拟电子产品真实服役环境将钎焊接头进行时效处理,借助于现代理化检测手段研究了时效钎焊接头的力学性能及其断裂机制。结果表明:在温度150℃、时间200h的条件下对钎焊接头进行时效处理验证了超声功率88W、超声时间60s和电场强度2kV/cm外能辅助条件下进行钎焊可明显改善接头的剪切强度。钎焊接头的断裂途径与断裂机制发生明显变化。无超声电场作用钎焊接头在IMC层发生脆性断裂;超声振动辅助下钎焊接头在IMC层和钎缝的结合面发生脆性和韧性的混合断裂,主要由颗粒状的IMC相和局部的"抛物线"剪切韧窝组成;超声振动和电场辅助作用的钎焊接头在钎缝发生韧性断裂,主要由尺寸较大的"抛物线"剪切韧窝组成。

With ultrasonic vibration and electric field, the brazing experiment of Sn2.5Ag0.7Cu0.1RE/Cu solder was carried out. In ordet to simulate the true environment of welded joint service condition, the welded joint was aging treated. The mechanical property and fracture mechanism of welded joint after aging treatment were researched by modern physical and chemical detection methods. The results show that the improvement of shear strength of welded joint after aging treatment condition of 150℃ × 200 h can be verified, when ultrasonic power is 88 W, time is 60 s, and electric field is 2 k V/cm. The brittle fracture of traditional soldering joint occurs in the IMC layer. The welded joint generates brittle and ductile fracture in the interface of the IMC layer and weld seam with ultrasonic vibration. The fracture is mainly composed of IMC phase and local ＂parabola＂ shear dimple. Particularly, the welded joint generates toughness fracture in weld seam assisting with ultrasonic vibration and electric field, and the ductile fracture is composed of large sized ＂parabola＂ shear dimple.