Sr元素对Al-Si-Zn-xSr钎料组织和性能的影响

研究了Zn,Sr元素对Al-Si-Zn钎料的铺展性能、显微组织、力学性能以及气密性的影响.结果表明,随着Zn元素含量降低,钎料的铺展面积可增大51%,6061铝合金钎焊接头的强度逐渐升高,达到120.5 MPa.当加入Sr元素后,钎料的铺展性能得到了显著提升,且随着Sr含量的增加,块状初生硅不断减少,共晶硅由针状转变为点状,并呈网状分布.当Sr元素质量分数为0.09%时,6061铝合金接头强度最高,为137.1 MPa.钎焊管路气密性测试结果表明,Al-0.2Si-77.8Zn及Al-2Si-62Zn两种钎料的气密性均逊色于Al-6.5Si-42Zn钎料.全浸试验后,Al-6.5Si-42Zn钎料的强度降低4.6%,而加入0.09%的Sr元素后钎料的强度降低3.6%.

Effect of strontium on microstructure and properties of AlSi-Zn-xSr filler metals

The effect of zinc and strontium element on the spreadability, microstructure, and mechanical properties of Al-SiZn filler metal has been investigated. The results indicated that the spread area was increased by 51% with decreasing Zn content, and the tensile strength of the brazed 6061 aluminum alloy joint was gradually increased to 120.5MPa. With the addition of Sr, the spreadability of Al-Si-Zn filler metal was significantly improved, the number of primary Si particles decreased and the eutectic Si was changed from acicular to fine fibrous morphology distributed in a netlike form. The strength of 6061 aluminum alloy joint reached the peak value of 137.1 MPa when the content of Sr was 0.09%. The air-tightness test of the brazed pipe showed that the tightness of Al-0.2Si-77.8Zn and Al-2Si-62Zn were inferior to that of Al-6.5Si-42 Zn. After the immersion test, the tensile strength of Al-6.5Si-42 Zn filler metal was decreased by 4.6%, while the Al-6.5Si-42Zn-0.09 Sr filler metal was only by 3.6%.