Ti40阻燃钛合金电子束焊接头组织与力学性能

采用不同工艺参数对2 mm厚Ti40阻燃钛合金进行电子束焊接(EBW),通过金相分析、电子探针(EPMA)、室温拉伸以及显微硬度测试对Ti40阻燃钛合金电子束焊接接头的显微组织和力学性能进行分析.结果表明,焊缝中分布着晶粒内部有片层状组织析出的β柱状晶和少量等轴β晶粒,熔合线到焊缝中心晶粒逐渐细化,无明显热影响区.接头中易产生气孔、裂纹等缺陷,通过添加直线扫描波形能够有效地控制焊缝气孔缺陷,从而提高接头的强度.添加直线扫描波形电子束焊的Ti40阻燃钛合金的抗拉强度仍可达到917 MPa,断口呈现出脆性断裂与韧性断裂的混合特征,焊缝区的硬度高于母材,其最大值为376HV.

Microstructure and Mechanical Properties of Ti40 Burn Resistant Titanium Alloy Joints by Electron Beam Welding

The Ti40 thick and Ti40 burn resistant titanium alloy in 2 mm was welded by electron beam with different welding parameter.Microstructure and mechanical properties of Ti40 burn resistant titanium alloy joints were studied by metallographic analysis,electron probe microanalysis,room-temperature tensile test and micro-hardness test.The results showed that β columnar crystal with intragranular slice layer structure and a few equiaxed β grain were distributed in the weld seam.Additionally,grain size of weld seam became finer from fusion line to the seam center and the heat affected zone is not distinct.Specifically,micro defects were easy to appear in the joints,such as pores and cracks,which could be effectively controlled by straight scanning waveform,and it would lead to the improvement of joint strength.The tensile strength of Ti40 burn resistant titanium alloy with straight scanning waveform EBW could reach at 917 MPa and the fracture was characterized with brittle and ductile fracture.The maximum hardness of the weld zone was 376HV which was higher than the base metal.