激光焊接Ti-4.5Al-3V-2Fe-2Mo合金的超塑成形组织及性能研究

Superplastic deformation microstructure and property of laser welded Ti-4.5Al-3V-2Fe- 2Mo alloy

摘要:

SP700钛合金具有优异的低温超塑性,本文对光纤激光焊接的SP700钛合金的超塑变形性能、组织演化及变形后的力学性能进行研究。结果发现,800℃锥形件变形时,焊接方向平行轧制方向具有更优的超塑变形性能,最大成形压力为0.8MPa,最大成形高度为75mm,较母材高20mm。随着变形量的增加,焊缝区粗大的柱状晶和焊接接头咬边逐渐消失,晶粒得到细化。经过33%的超塑变形量后,焊接方向平行和垂直轧制方向的抗拉强度均有所下降,但平行轧制方向、775℃成形的抗拉强度下降最小,仅为2.2%。锥形件和盒形件拉伸试样的断裂失效位置均在母材上。

Abstract:

SP700 titanium alloy has excellent superplasticity at low temperature, the paper used fiber laser welding SP700 titanium alloy to study the superplastic forming ability, microstructure evolution and RT tensile property after SPF. Result indicates that the welding direction parallel to the rolling direction of base material could have better superplasticity to form a cone part at 800℃, the max. pressure and cone height is 0.8MPa and 75mm, respectively, which is 20mm higher than base material"s. With the increase of deformation, the coarse columnar grains and weld undercut were eliminated and the grains was comparably fine. With about 33% deformation reduction, the tensile strength of materials with two welding directions were all decreased, and tensile strength of specimen with welding direction parallel to the rolling direction and formed at 775℃ only decreased by 2.2%. The fracture position all were on the base material for the cone part and tensile specimen.