搅拌摩擦焊接Mg-6Al-1Sn合金组织与性能研究

Microstructure and Properties of Mg-6Al-1Sn Alloy by Friction Stir Welding

对搅拌摩擦焊Mg-6Al-1Sn(AT61)合金板材在不同的焊接工艺参数下的组织与性能进行了研究。研究结果表明,在旋转速度为1 200r/min时,焊接速度为60~180mm/min及焊速为180mm/min时,转速为1 200~1 600r/min范围内都能实现良好连接,接头最大抗拉强度系数达到母材的88%,且焊核区的析氢速率低于母材,但电化学性能有所降低。母材中的第二相是Al8Mn5,没有检测到Mg2Sn相,在不同焊接工艺参数下接头组织与母材相比,第二相的类型不变,第二相的分布由条状变为颗粒状。

Mg-6 Al-1 Sn（AT61）magnesium alloy plates were successfully friction stir welded（FSW）.The effect of different parameters on microstructure and properties were investigated.The results showed that the sound welded joints were obtained at the constant rotational rate of 1 200 r/min when the welding speed ranged from 60—180 mm/min and at the constant welding speed of180 mm/min when the rotational rates ranged from 1 200—1 600 r/min,the best joint efficiency（i.e.,a ratio of the UTS of joint to the UTS of BM）was 88%,and the hydrogen rate in nugget zone（NZ）was lower than base material（BM）,but the electrochemistry performance was reduced.It was found that only Al8 Mn5 phase was observed in BM,no Mg2 Sn phase was detected.Compared with BM in microstructure,the type of secondary precipitates were insensitive to different welding parameters,and the distribution of secondary precipitates were transformed from strips into particles.