钛合金空心点阵超塑成形/扩散连接成形工艺和性能研究

Research on SPF/DB Process and Properties of Titanium Alloy Hollow Lattice

钛合金空心点阵是典型的承载–功能一体化结构,采用单轴拉伸方法,在不同温度、应变速率条件下测定TA15、TA32钛合金的超塑拉伸延伸率,最大延伸率分别达到1450%和950%,后在不同温度、压力条件下进行扩散连接试验。根据超塑拉伸和扩散连接试验,确定了超塑成形和扩散连接(Superplastic forming/diffusion bonding,SPF/DB)的最佳工艺参数为:920℃/1.5~2.0 MPa/2 h,制备了不同构型和几何参数的TA15、TA32钛合金空心点阵结构件。采用平压方法和三点弯曲方法测定了钛合金空心点阵的力学性能,压缩和弯曲强度最大值分别达到23.83 MPa、596MPa,通过有限元和试验分析的方法,研究了几何参数对钛合金空心点阵平压和弯曲性能的影响规律。采用单面加热方法,研究了钛合金空心点阵结构的隔热性能,在400℃/1 h条件下,隔热温差达到276.3~310℃。

Titanium alloy hollow lattice has excellent mechanical properties and physical functions,which is a typical load-function integration structure,and has good application prospects in future aircraft.The superplastic tensile elongation of TA15 and TA32 titanium alloys was measured by uniaxial tensile method at different temperatures and strain rates,the maximum elongation reached 1450%and 950%respectively.The diffusion bonding tests of TA15 and TA32 titanium alloys were carried out at different temperatures and pressures.According to the superplastic tensile and diffusion bonding tests,the optimal process parameters of superplastic forming and diffusion bonding were determined as 920℃/1.5–2.0 MPa/2 h.The hollow lattice structure of TA15 and TA32 titanium alloys with different configurations and geometric parameters were formed by superplastic forming/diffusion bonding(SPF/DB)process at optimal craft.The mechanical properties of titanium alloy hollow lattice were measured by flat compression and three-point bending method,the maximum strength reached 23.83 MPa and 596 MPa respectively.The influence of geometric parameters on the flat compression and bending properties of titanium alloy hollow lattice was studied by means of finite element analysis and experimental analysis.The thermal insulation performance of titanium alloy hollow lattice structure was studied by measuring the temperature difference between the cold and hot surfaces by single-side heating method.At 400℃/1 h,the thermal insulation temperature difference reached 276.3–310℃.