两种热处理状态2219铝合金对接接头补焊特性
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摘要
开展了运载火箭贮箱用2219铝合金CYS与C10S两种热处理状态VPTIG接头补焊研究,通过试验对补焊接头力学性能及微观组织进行分析。结果表明,焊接接头随补焊次数的增加,接头常温、低温断后伸长率均有不同程度的下降,一次补焊、二次补焊低温断后伸长率下降幅度分别为16. 7%,24. 6%。拉伸过程中,试样断裂位置均发生在焊接接头CYS侧熔合区,2219铝合金CYS态一侧熔合区晶粒度明显大于C10S态一侧。微观组织分析表明,接头力学性能下降的原因为补焊热循环导致共晶相发生晶间偏析,晶间的脆性共晶相长大,热影响区组织晶界相较母材原始组织同样发生长大现象,焊核区枝晶数量增加,熔合区、热影响区组织不同程度的长大共同导致了接头断后伸长率降低。
VP-TIG welded joint of 2219 aluminum alloy with different heat-treated state of CYS and C10S used in launch vehicle tank was repaired,the microstructure and mechanical properties of a repair welded joint was analyzed. The results show that the elongation of welded joint at the low and room temperature decreases with the increase of numbers of repair welding,which has declined to 16. 7% and 24. 6% respectively. During the tensile test,the fracture path of samples both occur in the side of 2219CYS fusion zone,and the grains size of the fusion zone in the side of 2219CYS is markedly larger than that of 2219C10S. The intercrystalline segregation of eutectic phase and growth and coarsening of brittle eutectic phase on boundary caused by welding thermal cycle are the main reason for the decreases of mechanical properties. The growth of grains in FZ and HAZ lead to the decrease of joint elongation.
VP-TIG welded joint of 2219 aluminum alloy with different heat-treated state of CYS and C10S used in launch vehicle tank was repaired,the microstructure and mechanical properties of a repair welded joint was analyzed. The results show that the elongation of welded joint at the low and room temperature decreases with the increase of numbers of repair welding,which has declined to 16. 7% and 24. 6% respectively. During the tensile test,the fracture path of samples both occur in the side of 2219CYS fusion zone,and the grains size of the fusion zone in the side of 2219CYS is markedly larger than that of 2219C10S. The intercrystalline segregation of eutectic phase and growth and coarsening of brittle eutectic phase on boundary caused by welding thermal cycle are the main reason for the decreases of mechanical properties. The growth of grains in FZ and HAZ lead to the decrease of joint elongation.
引文
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