2219 鋁合金穩(wěn)態(tài)蠕變本構(gòu)方程的建立Establishment of steady creep constitutive equation of 2219 aluminum alloy

在時(shí)效溫度為438~458 K、實(shí)驗(yàn)應(yīng)力為120~180 MPa 的條件下，采用RWS-50 型電子蠕變機(jī)對(duì)2219 鋁合金蠕變時(shí)效行為進(jìn)行研究。采用包含雙曲正弦函數(shù)的方程，通過(guò)對(duì)實(shí)驗(yàn)數(shù)據(jù)的線性回歸分析，確定應(yīng)力指數(shù)、蠕變激活能及相關(guān)常數(shù)，建立2219 鋁合金穩(wěn)態(tài)蠕變速率與實(shí)驗(yàn)應(yīng)力及時(shí)效溫度之間的關(guān)聯(lián)本構(gòu)模型。結(jié)果表明：隨著實(shí)驗(yàn)應(yīng)力的增大和時(shí)效溫度的升高，2219 鋁合金的穩(wěn)態(tài)蠕變速率增大，且蠕變曲線在第二階段的持續(xù)時(shí)間縮短；依據(jù)本構(gòu)方程計(jì)算出該鋁合金在各條件下的穩(wěn)態(tài)蠕變速率與其實(shí)驗(yàn)值的平均相對(duì)誤差為4.22%，表明該本構(gòu)方程可為2219 鋁合金蠕變時(shí)效成形工藝的制定提供理論依據(jù)。

The creep aging behavior of 2219 aluminum alloy was studied on the RWS-50 electronic creep testing machine at 438-458 K with the stress range from 120 to 180 MPa. By adopting the equations including hyperbolic sine function and by linear regression analysis of experimental data,the stress index,the creep activation energy and the related constants were determined. The constitutive relationship among steady creep strain rate,tested stress and aging temperature of 2219 aluminum alloy was obtained. The results show that the steady creep rate increases with the increase of tested stress and aging temperature. And the second step in creep curves becomes short. The average relative error of steady creep strain rate between theoretical value computed by the constitutive equation and actual value is only 4.22%,and the constitutive equation can provide theoretical basis for formulating creep aging forming process of 2219 aluminum alloy.

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