热处理对激光沉积TC4/TC11组织和性能的影响

Effect of Heat Treatment on Microstructure and Properties of Laser DepositionTC4 / TC11

摘要:

通过对激光沉积TC4/TC11钛合金直接过渡件沉积态和热处理态的显微组织、静载力学性能、拉伸断口及显微硬度进行对比研究,探索改善激光沉积TC4/TC11钛合金组织,进而提高综合力学性能的途径。研究结果表明,沉积态试样在970 ℃热处理后α板条的长宽比小于沉积态和退火态,两侧组织均呈现典型的网篮组织特征且更为均匀,晶界α相彻底消失,过渡界面基本消失,使得TC4/TC11组织参数最优化；沉积态、去应力退火和固溶时效(最优热处理参数)热处理后试样的拉伸断口为韧性断口且均断在了TC4侧,其中固溶时效热处理后试样强度没有明显降低,塑性得到显著提高,具有良好的综合力学性能；当热处理温度提高到970 ℃(最优热处理参数),该试样沿着整个过渡界面显微硬度值分布最均匀、差异最小,基体与过渡界面处显微硬度值变化也最小。

Abstract:

By comparing the microstructure, static mechanical properties, tensile fracture and microhardness of laser deposited TC4 / TC11 titanium alloy direct transitional parts in the as-deposited and heat-treated states, the approaches to perfect the microstructure of laser deposition TC4/TC11 alloy so as to improve its integrated mechanical properties were explored,. Results show that after the as-deposited sample undergoes 970℃ heat treatment, its length-width ratio of α laths is less than that of as-deposited and annealed samples. The microstructure on the two sides is featured by basket-weave structure and more even. In addition, the grain boundary α disappears entirely. There is almost no existence of transitive interface, which optimizes the textural parameters of TC4/TC11 titanium alloy. For all the as-deposited, relieved-stress and solution aging samples (optimal heat treatment parameters), their tensile fractures are tough fracture and their fracture sections are all on the side of TC4 titanium alloys. Among them, the strength of solution aging sample is not reduced greatly. Moreover, its plasticity is remarkably enhanced. So it has excellent integrated mechanical properties. When the temperature of the heat treatment raises to 970℃ (optimal heat treatment parameters) microhardness of TC4/TC11 titanium alloys is uniform along the whole transitive interface with minimum differences. At the same time, microhardness changes the most slightly on the matrix and transitive interface.