外应力对GH4169合金时效强化作用的影响

Effects of external stress on age hardening of GH4169 alloy

采用应力保载与时效相结合的方法对GH4169合金进行应力时效热处理,通过检测时效后合金的屈服强度和抗拉强度来衡量外应力施加对合金时效强化效果的影响。结果表明,时效初期外应力会强烈促进γ″相形核析出,合金强化效果显著;随时效时间的增加,时效中后期合金强化效果逐渐减弱;长时时效8h后外应力促进形核作用导致γ″相尺寸减小,使得合金强度反而低于无外应力条件。

External stress-aging heat treatments were conducted on GH4169 alloy with stress holding combined with aging with the universal testing machine.Yield strength and tensile strength of the alloy after aging were tested to judge the influence of external stress on the hardening effects of the alloy.The results showed that the nucleation and precipitation of theγ″phase was strongly promoted by external stress in the early stage of aging producing remarkable strengthening effects.With the increase of aging time,the strengthening effect of alloy was gradually weakened in the intermediate and late stages of aging.After 8 h of aging,nucleation was promoted and the size ofγ″phase was reduced with the external stress,making the strength of the alloy lower than that under the non-external stress condition.