异种铝合金摩擦塞补焊工艺与组织性能

Study of technology and structure property on friction plug welding of dissimilar aluminum alloy

关键词:  铝合金  摩擦塞补焊  微观组织  显微硬度  力学性能

Key words:  aluminum alloy  friction push plug welding  microstructures  micro-hardness profiles  mechanical properties

摘要:

采用顶锻式摩擦塞补焊方法，以2219-T6铝合金为塞棒材料，分别对8 mm厚2024-T3和7075-T6两种铝合金FSW接头进行了摩擦塞补焊试验研究，深入探讨了不同焊接压力下塞补焊接头的微观组织、显微硬度、力学性能及断口形貌特征. 结果表明，塞棒和母材或FSW焊缝是由等轴晶进行过渡，获得了紧密结合的接头，热力影响区和热影响区晶粒发生长大. 整个塞补焊接头塞棒区软化最严重，硬度在85 ~ 95 HV之间. 2024铝合金塞补焊接头抗拉强度和断后伸长率分别达到了母材的70%和65%以上，7075铝合金塞补焊接头抗拉强度和断后伸长率分别达到了母材的62%和48%以上. 塞补焊接头断裂模式为韧性特征.

Abstract:

Based on the friction push plug welding method, the investigations of friction plug welding experiments for AA2024-T3 and 7075-T6 friction stir welds with 8 mm thickness by using the AA2219-T6 plugs were performed, the varying features of microstructures, micro-hardness profiles, mechanical properties and fracture modes of various welding pressure have been analyzed in detail. The results showed that tight joints were obtained between plug and base metal or FSW welds. The transition zone from plug to base metal or FSW welds consisted of equiaxed grains. Grain growth occurred in the thermo-mechanically affected zone and heat affected zone. Micro-hardness of plug zone was 85~95 HV, which is the weakest areas of whole FPW joints. The tensile strength and elongation of AA2024 FPW joints can reach above 70% and 65% of the base metal respectively. The tensile strength and elongation of AA7075 FPW joints can reach above 62% and 48% of the base metal respectively. The fracture modes of FPW joints were ductile.