不同返修次数对6082-T6铝合金对接接头疲劳性能的影响

对不同返修次数的高速列车用6082-T6铝合金搅拌摩擦焊对接接头进行脉动拉伸疲劳试验,并对疲劳断口进行扫描观察与分析。结果表明,焊接接头指定寿命为1×107次的中值疲劳极限随返修次数的增加而升高。搅拌摩擦焊返修两次时焊接接头的疲劳极限强度较高,疲劳试验中的试件断裂位置主要集中在背面焊缝边缘。启裂区和扩展区疲劳纹清晰,终断区为浅韧窝型韧性断口。

Effect of different times of repair on fatigue properties of 6082-T6 aluminum alloy butt joints

TThe 6082-T6 aluminum alloys butt-joints of different times of repair,which is used for high-speed train,were studied respectively through pulsating tensile fatigue test and scanning analysis for the fatigue fractures.The results showed that:the welding joints median value fatigue limit strength that specifies life of 1×107 increased with the increase of repair times.When the friction stir welding was repaired two times,the fatigue limit strength of welded joint was higher,the fracture location of the FSW specimen was mainly concentrated on the edge of the back surface welding seams.The scanning photos showed that the panorama of the fracture was like fibrous;the fatigue beach on the crack initiation zone and extending zone was vivid;the final broken zone was the toughness fracture of low dimple type.