同质异种热处理状态铝合金搅拌摩擦焊接头组织与性能

Microstructure and Mechanical Properties of the FSWed Joints Between 2219MCS Ring and 2219C10S Barrel

开展了2219MCS叉形环和2219C10S筒段组成的接底接头的搅拌摩擦焊工艺试验,分析了焊接速度、2219MCS叉形环位置对接头组织形貌、显微硬度、力学性能的影响规律。结果表明：2219MCS叉形环的原始粗大组织晶粒导致其无论位于前进侧还是后退侧,均是整个接头的薄弱环节。接头显微硬度呈现出典型的＂W＂型分布,叉形环一侧的热机影响区的显微硬度最低。在焊接参数相同时,叉形环位于后退侧的力学性能优于其位于前进侧;当焊接速度为180~220 mm/min且叉形环为后退侧时,其接头综合性能最优,抗拉强度可达到330 MPa,低温抗拉强度可达到420 MPa,延伸率超过3.5%,正弯性能均可以达到180°无裂纹,但是2219MCS母材开始出现裂纹,而背弯性能较差,并且背部裂纹沿着2219MCS热机影响区一侧起裂、扩展。

An extensive investigation has been carried out on the friction stir welded butt joint consisting of a2219 MCS ring and a 2219C10 S barrel,and the effect of welding speed and the location of the 2219 MCS ring on the microstructure,microhardness distribution and mechanical properties of the butt joint has been systematically analyzed in this paper. The results showed that the 2219 MCS ring whether located in the advancing side or retracting side is the weak link of the joint due to the original coarse grain. The microhardness distribution of the joint showed the typical＂W＂type with the TMAZ of the 2219 MCS ring the lowest. The optimized investigation results showed that the performance of the joint with the 2219 MCS ring located in the retracting side is more than the joint with the 2219 MCS ring located in the advancing side. When the welding speed is 180 to 220 mm / min and the 2219 MCS ring located in the retracting side,the room temperature mechanical strength can be up to 330 MPa,the low temperature strength 420 MPa,and the ductility all more than 3. 5%. The face bending angle can reach 180° without crack on the joint,but some cracks occurred on the parent metal of the 2219 MCS ring. The back bending performance is so poor,and the crack occurred and spreaded along the TMAZ of the 2219 MCS ring.