【摘要】 采用直接扩散连接Ti3Al和Ti2AlNb合金,研究了连接压力、连接温度、保温时间等工艺参数对接头界面组织形貌及性能的影响。利用扫描电镜、能谱分析和X射线衍射等方法观察分析了界面组织结构,并测试了接头的力学性能。结果表明:直接固相扩散连接接头的典型组织为Ti3Al/O相+α2相过渡层/富B2层/Ti2AlNb。当连接温度为1000℃,保温时间60min,连接压力为5MPa时获得的接头室温抗剪强度为635MPa,室温抗拉强度为795MPa,均断裂于Ti3Al母材一侧。经1000℃/60min热循环后Ti3Al母材的抗拉强度下降至原始母材的76%。连接温度低于950℃或保温时间小于60min会导致未焊合等缺陷;温度高于1050℃或保温时间超过120min则导致Ti3Al发生相变。更多还原

【Abstract】 Ti3Al and Ti2 AlNb alloys were joined by direct diffusion welding.The influence of bonding pressure,bonding temperature and holding time on the interface morphology and property of the joint was studied.The interface structure was analyzed by SEM,EDS and XRD,and the mechanical properties of joints were tested.The results show that typical interface structure of direct diffusion bonding joints is Ti3Al/O-phase and α2-phase/B2-rich phase/Ti2 AlNb. When bonding temperature is1000℃,holding time is 60 min,bonding pressure is 5MPa,the shear strength could reach 635 MPa and the tensile strength could reach 795 MPa.Both joints fracture at the Ti3Al-base alloy.After thermal cycling(1000℃/60min),the tensile strength of Ti3 Al decreases to 76% of the original strength.Welding defects occur when bonding temperature is below 950℃ or holding time is less than 60 min.The bonding temperature higher than 1050℃ or holding time more than 120 min will lead to phase transition of Ti3 Al.更多还原