热处理对Ti2AlNb合金电子束焊接接头组织和性能的影响

Effect of heat treatment on microstructure and properties of electron beam welding Ti2Al Nb alloy joint

采用光学显微镜、拉伸试验机及显微硬度计研究了热处理对Ti2A1Nb合金电子束焊接接头组织与性能的影响。结果表明，Ti2A1Nb合金电子束原始焊接组织由仪：相、B2相和O相组成，经不同温度的热处理获得不同形态的O相，以强化焊缝强度。经850℃×2h炉冷热处理后室温和高温力学性能最佳，韧性也最佳。Ti2A1Nb合金电子束焊接接头经850℃热处理可提高焊缝显微硬度，断口呈现解理断裂和韧窝断裂相结合的特征。

The effect of heat treatment processes on microstructure and mechanical properties of electron beam welding Ti2A1Nb alloy was investigated by means of optical microscope, tensile tester and microhardness tester. The results show that the as-welded microstructure of laser-welded Ti2A1Nb alloy is composed of massive primary c% phase, B2 phase and O phase transformation mierostructure. The various O phases can be obtained by different heat treatment processes. The strength of the weld beam is enhanced by the O phase. The best room temperature and high temperature tensile strength appears at the 850 ℃ for 2 h. The mierohardness of electron beam welding Ti2A1Nb alloy welded joint is enhanced by heat treatment at 850℃. The fracture appears both cleavage fracture and dimple fracture.