基于激光预焊芯板夹层的超塑成形/扩散连接先进工艺

Advanced technology of superplastic forming and diffusion bonding with laser pre-welding core sheets

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。

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%.