TiAl 基合金格栅结构预制空位拉制成形研究

To solve the problems of difficult preparation and poor formability of TiAl based alloy sheet and difficult to fabricate the grid structure by traditional method, the precutting empty seam stretch forming method was used to fabricate TiAl based alloy grid structure. TiAl based alloy was prepared by hot pressing sintering of prealloyed powder under the sintering temperature of 1150 ℃, sintering pressure of 30 MPa and holding time of 2 h. The precutting empty seam stretch forming temperature of TiAl based alloy sheet is 990 ℃ and the strain rate is 0. 001 s^-1. The results show that with the increase of the deformation length of the sheet, the shape of the seams is formed from the longitudinal diamond to the square to the transverse diamond, and the distribution of the seams along the sheet is relatively uniform, which is consistent with the simulation results. The maximum tensile strain position of the sheet is transferred from the corner of the seams to the intersection of the seams, and the maximum tensile strain value is 0. 5. When the maximum deformation length of TiAl based alloy sheet with precutting empty seams reaches 89 mm, the elongation of deformation area is 112%.