(核工業(yè)理化工程研究院 四所，天津 300180)
摘 要: 針對高強鋁合金蠕變數(shù)據(jù)存在冪律失效而難于擬合的問題，采用Monkman-Grant關(guān)系式，在經(jīng)典時間溫度參數(shù)模型的基礎(chǔ)上，推導(dǎo)4種不同形式的速率溫度參數(shù)模型。根據(jù)高強鋁合金7075在34.4~148.9 ℃下的蠕變數(shù)據(jù)，利用多元線性回歸方法，計算得出基于不同形式速率溫度參數(shù)的材料穩(wěn)態(tài)蠕變方程。結(jié)合統(tǒng)計檢驗方法，評價不同模型下蠕變方程的擬合效果。結(jié)果表明：在顯著性水平5%的條件下，OSD’模型下穩(wěn)態(tài)蠕變速率實測數(shù)據(jù)與擬合結(jié)果的對數(shù)差值不滿足正態(tài)分布。OSD’、LM’模型下擬合數(shù)據(jù)的對數(shù)值無法完全落入理想擬合線雙側(cè)96.5%的置信區(qū)間內(nèi)。RMB’、MH’模型下實測與擬合對數(shù)值之間的線性相關(guān)系數(shù)均大于0.994，對應(yīng)的殘差平方和分別為0.2797、0.2800。基于RMB’、MH’模型的蠕變本構(gòu)方程可以較好地描述7075鋁合金在實驗條件范圍內(nèi)的穩(wěn)態(tài)蠕變行為。
關(guān)鍵字: 速率溫度參數(shù)；高強鋁合金；冪律失效；蠕變本構(gòu)方程；統(tǒng)計檢驗
（Institute of Physical and Chemical Engineering of Nuclear Industry, Tianjin 300180, China）
Abstract:Based on Monkman-Grant equation and time temperature parameter, four different rate temperature parameter models were proposed to resolve the difficulty of creep data fitting when power-law breakdown appears in high strength aluminum alloy. The 7075 creep data were fitted into different rate temperature parameter models to obtain the steady creep rate equations by multiple linear regression. The effectiveness of model prediction were discussed in comparison of different models by statistical test methods. The results demonstrate that when significance level is 5%, the logarithmic difference distribution of measured and fitted data by OSD’ model do not satisfy normal distribution. The fitted logarithmic creep rate by OSD’ and LM’ models could not completely drop into 96.5% confidence intervals of ideal fitted line. The regression curves are calibrated by logarithmic values of measured and fitted data by RMB’ and MH’ models, which linear correlation coefficients are greater than 0.994. The sum of squared residuals of RMB’ and MH’ models are 0.2797 and 0.2800, respectively. The steady state creep behavior of 7075 aluminum alloy in experimental conditions can be well described by creep constitutive equations of RMB’ and MH’ models.
Key words: rate temperature parameter; high strength aluminum alloy; power-law breakdown; creep constitutive equation; statistical test
