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研究了大变形量冷轧Ti-15-3合金的时效析出行为和时效过程中力学性能的变化。冷变形使Ti-15-3合金中形成部分纳米晶。冷变形合金在450～650℃时效时,从β相纳米晶区析出极为细小的针状α相,而从β相非纳米晶区析出的α相随着时效温度的升高由针状逐渐长大为条状,进而演变为凸透镜状。冷变形合金在450℃时效4h后,硬度达到了峰值,HV为5328MPa。450℃时效时在硬度峰值处同样达到了强度峰值,屈服强度和抗拉强度分别可高达1483和1562MPa。时效温度升高,达到峰值硬度的时间缩短,硬度值大幅度下降。650℃时效后的强度和硬度均低于时效前,粗大的透镜状析出相、纳米晶的长大以及位错密度的急剧下降是650℃时效时硬化效果消失的主要原因。不同时效工艺下的强度和硬度的变化规律相似,性能的变化与时效过程中析出相的状态有关。
The aging behavior and the mechanical properties of Ti-15-3 alloy during cold rolling were investigated. Cold deformation of Ti-15-3 alloy to form part of the nanocrystalline. When the cold deformation alloy aged at 450-650 ℃, very fine needle-shaped α-phase precipitated from β-phase nanocrystallites, while the α-phase precipitated from β-phase non-nanocrystalline precipitated gradually from needle-like as the aging temperature increased Large strip, and then evolved into a lenticular shape. Cold deformation of the alloy after aging at 450 ℃ 4h, the hardness reached a peak HV is 5328MPa. 450 ℃ aging at peak hardness also reached the peak intensity, yield strength and tensile strength, respectively, up to 1483 and 1562MPa. The aging temperature increases, the time to peak hardness is shortened, and the hardness decreases sharply. The strength and hardness after aging at 650 ℃ are lower than those before aging. The main reason for the disappearance of the hardening effect at 650 ℃ is that the coarse lenticular precipitates, the growth of nanocrystals and the sharp drop of dislocation density are the main causes. The variation of strength and hardness under different aging processes are similar, and the change of performance is related to the state of precipitated phase during the aging process.