锤击对铝合金焊接接头性能的影响

通过力学性能试验和SEM技术对不同锤击焊接强化工艺的LY12CZ高强铝合金试样进行了力学行为研究和组织分析。结果表明：锤击处理可明显强化焊接接头，特别是随焊锤击能够明显强化焊趾，提高焊件的强度和塑性。与常规焊相比，其抗拉强度提高26％，延伸率增加50％。常规焊件断口形貌上存在较多树枝晶；随焊锤击件断口为韧窝和撕裂棱形貌，焊后锤击的断口形貌则介于常规焊件和随焊锤击件之间，可观察到韧窝和撕裂棱，亦可观察到少量树枝晶，晶粒细化是锤击工艺的主要强化机理。

Effect of peening on property of welded joint of aluminum alloy

The mechanical behavior and metallurgical structure of welded joints of LY12CZ aluminum alloy, which were made by same welding process but treated by different peening methods, were studied by means of mechanical test and SEM technology. Results shows that penning in the weakest region of welded joint may strengthen welded toe obviously, and substantially improve ductility and strengthen of weldment. Welding with trailing peening process led to a 26% increase in tensile strength, a 50% increase in elongation rate; A lot of dendrites can be seen in normal weldment fracture region; Dimples and tear ridges existed in fracture region of weldment by welding with trailing peening , but no dentrites were observed. By peening after welding, dendrites and tear ridges were coexisted in the tensile fracture region. In our opinion, grain refinememt is the main reason of strengthening.