焊接温度对5A06铝合金SPS钎焊接头组织和性能的影响

EffectSofSBrazingSTemperatureSonSMicrostructureSandSPropertiesSofSSparkSPlasmaSBrazedSJointSofS5A06SAluminumSAlloy

摘要:

5A06铝合金具有中高强度,优良的腐蚀稳定性以及良好的导热和机械加工性能,在雷达液冷组件和波导结构件等精密制造领域广泛应用。本文采用Al-20Cu-5Si-2Ni钎料,通过放电等离子烧结技术实现5A06铝合金SPS钎焊,研究了焊接温度对连接接头组织和性能的影响。当焊接温度为510~530℃，压力为4MPa,保温时间为10min时,接头抗拉强度随温度上升而增大,最大接头强度为152MPa,断口呈现韧性断裂特征,韧窝细小均匀。在低温钎料、焊接压力、脉冲电场和短时保温的综合作用下,SPS钎缝变窄,晶粒细小,脆性相分散,界面发生快速元素扩散,微观焊合率提高,形成的细小Mg₂Si和Si颗粒能够显著提升接头力学性能。

Abstract:

5A06 aluminum alloys are widely used in the precise manufacturing structures such as liquid-cooling and waveguide components because of high strength, excellent corrosion resistance as well as good thermal conductivity and machinability. In this paper, spark plasma brazing by using Al-Cu-Si-Ni solder foil is performed to realize the joining of 5A06 aluminum alloy. The influence of brazing temperature on microstructure and mechanical properties of brazed 5A06 alloy joints was investigated. The results show that at the bonding temperature of 510~530℃, pressure of 4MPa and holding time of 10min conditions, the tensile strength of welded joint increase with temperature increasing. The maximum tensile strength is 152 MPa, wherein ductile fracture surface mainly composed of fine and homogenous dimples is obtained. Under the combined effect of low melting point solder, welding pressure, pulse electric field and short holding time, the brazing zone is getting thinner while matrix grains are finer and brittle phases are more dispersed. Meanwhile, the interfacial atomic diffusion and reaction are enhanced that the microscopic metallurgical bonding strengthened by Mg2Si, Si particles is obtained.