摘要
GH738合金是沉淀硬化型镍基高温合金，含有Al、Ti等强化元素。一般而言，难于焊接，且焊缝的力学性能与母材相比也往往有较大下降。本研究采用激光焊对GH738合金冷带进行焊接，对焊缝进行机械处理和热处理后研究了焊缝的微观组织、力学性能的变化情况。结果表明，激光焊接得到的焊缝和母材之间的熔合线明显，未观察到明显的热影响区。对焊缝进行滚压处理后，焊缝样品的拉伸性能接近母材的水平。经过固溶热处理后，焊缝样品的延伸率可由不足20％上升至40％以上。再经时效处理后，焊缝的强度高于母材。微观组织观察发现，经固溶和时效热处理后的焊缝样品，其熔合线附近的晶粒发生了再结晶。时效热处理后的焊缝处有大量的Ti（C，N）析出相，提高了焊缝的强化效果。
GH738 alloy is a precipitation hardening nickel-base superalloy which includes lots of strengthening elements such as Al and Ti. GH738 alloy＇s welding is quite difficult and the mechanical properties of the welding seam usually decline significantly compared to base materials. In this paper, laser welding on the GH738 alloy was carried out, and the aswelded samples were treated with rolling and heat treatment. The metallographic structures and mechanical properties after treatment were investigated. The results show that before any treatment, the fusion line was obviously observed between the welding seam and base materials, with barely heat affected zone found. After rolling treatment, the tensile property of as-welded samples was close to base materials; furthermore, after solid solution treat- ment, the elongation increased from less than 20% to 40% above; after that, with aging treatment, the mechanical properties of welding seams were better than that of base materials. Near the fusion line, the grain recrystallization was observed for both solid solution treatment and aging treatment. As for aging treatm ted within welding seams, which helped to enhance ent, plenty of Ti（C, N） phase precipita welding seams strength.
出处
《金属材料研究》
2016年第1期6-12,共7页
Research on Metallic Materials
