TC4/TC17电子束焊接接头组织及高温拉伸性能研究

Microstructure and mechanical properties of TC4/TC17 electron beam Welded joints

摘要:

针对TC4/TC17异种钛合金开展电子束焊接研究,并进行了高温(400℃)拉伸试验。结果表明,在焊接热循环作用下,热影响区和焊缝组织与母材相比发生了显著变化；TC4侧热影响区组织为马氏体；TC17侧热影响区则是亚稳定β相,焊缝处观察到粗大的柱状晶。TC17母材硬度高于TC4母材硬度,焊缝中心硬度最高。在400℃下,TC17母材的抗拉强度最好；焊接接头的抗拉强度与TC4母材的相当；TC4/TCI7电子束焊焊接接头的断口表面存在尺寸较大,少而浅的韧窝,韧窝形状呈椭圆形,表现出较好的塑性。

Abstract:

Electron beam welding was carried out on TC4/TC17 dissimilar titanium alloy, and tensile tests were carried out at 400℃. The results show that there were significant changes in heat-affected zone and weld microstructure compared with base material with the action of welding thermal cycle. The microstructure of heat-affected zone on TC4 side was martensite. The heat-affected zone of TC17 side was metastable β phase, and coarse columnar crystals were observed at the weld. The hardness of TC17 base material was higher than that of TC4 where the hardness of weld center was the highest. The tensile strength of TC17 base metal was the best at 400℃，meanwhile the tensile strength of welded joint was similar to that of TC4 base metal. The fracture surface of TC4/TCI7 electron beam welded joint was characterised by large size, few and shallow tough nests, which were oval in shape and showed good plasticity.