【摘要】 针对Ti₂AlNb合金进行直接固态扩散焊，研究压力对合金扩散焊接头组织与性能的影响，使用扫描电镜分析焊接接头的显微组织随压力的变化规律，对不同压力下的焊接接头进行室温拉伸实验，分析接头性能随压力的变化趋势以及接头的断裂机制。结果表明：随着压力的增加，试样表面的变形量增大，在高温下变形区域发生动态回复与再结晶，促进了连接面处孔洞的愈合，焊合率因此逐渐升高；Ti₂AlNb合金扩散焊接头可以分为再结晶区、变形区以及母材三部分，其中再结晶区主要由等轴的B2相以及α₂相组成，随着扩散焊压力的增加，再结晶区的宽度明显变宽；焊接接头的强度随着压力的增加先升高后下降。当焊接工艺参数为960℃-60 MPa-120 min时获得的焊接接头性能最好，其抗拉强度为972 MPa，达到母材强度的98%；过大的压力使得再结晶晶粒粗化，且再结晶区和变形区交界处产生裂纹，导致接头性能反而恶化。更多还原

【Abstract】 Direct solid diffusion bonding of Ti₂AlNb alloy was carried out, and the effect of pressure on the microstructure and mechanical properties of the bonded joints was studied. Scanning electron microscopy was used to analyze the microstructure of the welded joint under different pressures. The tensile property of the joints with different pressures was tested and the variation trend of the tensile property with pressure was analyzed. The results show that with the increase of pressure, the deformation within the sample surface layer increased, and the dynamic recovery and recrystallization occurred in the deformed area at high temperature,which promotes the closing of voids on the bonding interface and the rise of well-bonded areas. A diffusion bonded joint of Ti₂AlNb alloy can be divided into three parts:recrystallization zone, deformation zone and base metal. The recrystallization zone is mainly composed of equiaxed B2 phase and α₂ phase. With the increase of pressure, the width of the recrystallization zone becomes wider obviously, and the strength of the bonded joint increases first and then decreases. When the welding parameters are 960 ℃-60 MPa-120 min, the welded joint had the best performance, and its tensile strength is 972 MPa, reaching 98% of the base metal. An excessive pressure coarsened the recrystallization grains, and cracks appeared at the interface of the recrystallized zone and the deformation zone, which deteriorated the performance of the bonded joint.更多还原