锻造工艺对Ti-6.5Al-1Mo-1V-2Zr合金大规格棒材的组织与性能的影响

摘要

研究三种锻造工艺条件下 Ti−6.5Al−1Mo−1V−2Zr 合金大规格棒材的力学性能、微观组织和拉伸断口。结果表明：采用拔长方式在β区高温和低温分别进行开坯锻造和成品锻造，获得的棒材的组织为粗大的魏氏组织，力学性能特别是塑性差，室温拉伸断口为脆性断口；采用镦拔方式在β区高温进行开坯锻造，再采用拔长方式在α+β区进行成品锻造，获得棒材的组织为双态组织，具有最佳的综合力学性能，室温拉伸断口为塑性断口。要获得合格的 Ti−6.5Al−1Mo−1V−2Zr 棒材，关键是开在坯锻造阶段进行充分镦拔以破碎铸锭原始组织，并在成品锻造阶段控制锻造温度和变形量。%The mechanical properties, microstructure and tensile fracture of Ti−6.5Al−1Mo−1V−2Zr large section bars produced by three diffrent forging processes were investigated. The results show that when billet forging and finish forging were conducted by means of fullering at high and low temperature ofβ-region, respectively;the microstructure of forged bar is coarse Widmanstaten structure; the mechanical properties, especially the reduction of cross-sectional area, are poor, and the room temperature tensile fracture presents a brittle feature. While billet forging was carried out by upset-fullering at high temperature of the β-region, and finish forging was proceeded through fullering at (α+β)-region, the microstructure of forged bar was a duplex structure, the bar has better comprehensive mechanical properties, and the room temperature tensile fracture reveals a ductile feature. In order to obtain qualified Ti−6.5Al−1Mo−1V−2Zr alloy bar, it is the key that as-cast microstructure should be completely broken during billet forging, and the forging temperature and deformation are also well controlled upon finishing forging.