(南京航空航天大学 机电学院,南京 210016)
摘 要: 针对传统多层空心整体结构在超塑成形/扩散连接(SPF/DB)工艺过程中存在的中心夹层焊接可靠性差的关键工艺问题,以某飞行器TC4(T-6Al-4V)钛合金舵体四层空心复合整体结构为对象,提出了激光预焊芯板夹层的超塑成形/扩散连接新工艺。基于有限元软件模拟仿真分析及相应的试验研究,采用激光预焊芯板夹层的SPF/DB先进工艺,进行某飞行器TC4钛合金四层空心复合整体舵体零件的研制。结果表明:运用SPF/DB新工艺,在920 ℃、真空度为5×10-3 Pa、最大气压压力为1.2 MPa 条件下超塑成形/扩散连接成形出合格的舵体零件,其焊合率达95%以上,壁厚分布均匀性大于90%,晶粒尺寸长大控制在35%以内。
关键字: TC4钛合金;激光焊接;超塑成形;扩散连接;有限元模拟;舵体
(College of Mechanical and Electrical Engineering,
Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China)
Abstract:In view of the traditional multilayer hollow structure superplastic forming and diffusion bonding (SPF/DB) process which leads to a poor reliability of welding core interlayer, a new method based on laser pre-welding for core layers was raised up for the aircraft rudder of four TC4 (Ti-6Al-4V) titanium alloy layers with composite hollow structure. With the experimental study and corresponding finite element simulation analysis carried out, a forming method of the four layers aircraft rudder body part was developed based on the new SPF/DB process of laser pre-welding core sheets. The results show that: adopting the new SPF/DB technology under the conditions that at the temperature of 920 ℃, vacuum degree of 5×10-3 Pa, and the maximum pressure of 1.2 MPa, the rudder body part is qualified reaching a welding rate above 95% and wall thickness distribution uniformity greater than 90%,and controlling the grain size growth in 35%.
Key words: TC4 titanium alloy; laser welding; superplastic forming; diffusion bonding; finite element simulation; rudder