在大气环境中,对Mg-Zn-Al钎料进行超声振动作用下的铺展,超声时间分别为1,2,3,4s,并与钎剂作用下的钎料铺展行为进行对比。采用体视显微镜观察钎料在超声及钎剂作用下的铺展形貌。采用光学显微镜观察钎料铺展初始端、铺展末端及铺展后钎料的微观组织形貌。结果表明:超声振动作用下的Mg-Zn-Al钎料沿基体表面作受迫铺展,声空化作用于液态钎料产生的冲击波可以破碎基体表面的氧化膜,使液态钎料与母材发生润湿,母材溶解的深度仅有0.12mm。超声时间为2s时,钎料铺展面积最大。超声声空化作用破碎液态钎料在凝固期间产生的α-Mg固溶相及MgZn共晶相,使铺展后的钎料显微组织得到细化。
The spreading and wetting behavior of Mg-Zn-Al solder under the action of flux and ultrasonic vibration was conducted in atmosphere.The ultrasonic vibration time was 1,2,3,4s,respectively.The spreading morphology and microstructure of the solder was investigated by optical microscope.The results show that the Mg-Zn-Al solder is forced spread under the effect of ultrasonic vibration along the base metal.The impact wave induced by ultrasonic cavitation can break the oxide film on the surface of base metal and the solder,which can promote the solder to wet the base metal.The depth of the dissolved base metal is only 0.12 mm.When the ultrasonic time is 2s,the spreading area reaches its maximum.The ultrasonic cavitation can break the columnar crystals of Mg-Zn eutectic phase and the dendrite crystals ofα-Mg,which can refine the microstructure of the Mg-Zn-Al solder.