【摘要】：工業(yè)純鈦TA2中低溫蠕變行為存在顯著的溫度及應(yīng)力相關(guān)性。基于外加應(yīng)力水平和蠕變應(yīng)變的變化關(guān)系,確定不同蠕變溫度下的門檻應(yīng)力水平。根據(jù)短時蠕變實驗數(shù)據(jù),利用包含穩(wěn)態(tài)蠕變速率的本構(gòu)方程外推穩(wěn)態(tài)蠕變速率,而后進(jìn)行兩組相對長時的蠕變實驗,證明了工業(yè)純鈦中低溫蠕變存在穩(wěn)態(tài)蠕變階段。利用穩(wěn)態(tài)蠕變速率與應(yīng)力關(guān)系,計算出工業(yè)純鈦室溫蠕變應(yīng)力指數(shù)為6.96,也說明了外推穩(wěn)態(tài)蠕變速率的可靠性。中低溫蠕變激活能隨著蠕變進(jìn)行變化不大(≈60 k J/mol),但一直大于以位錯為變形主導(dǎo)機(jī)制的變形激活能(30~40 k J/mol),表明孿晶對于工業(yè)純鈦中低溫蠕變發(fā)展整個階段均起重要作用。根據(jù)蠕變后試樣孿晶結(jié)構(gòu)隨溫度的變化解釋了TA2蠕變行為的溫度相關(guān)性,同時也證明了孿晶對于TA2蠕變行為的重要性.
[Abstract]:The low temperature creep behavior in commercial pure titanium (TA2) is significantly correlated with temperature and stress. The threshold stress level at different creep temperatures is determined based on the relationship between the applied stress level and creep strain. According to the experimental data of short time creep, the steady state creep rate is extrapolated by the constitutive equation including steady state creep rate, and then two groups of relatively long creep experiments are carried out. It is proved that there is a steady state creep stage in medium and low temperature creep of commercial pure titanium. Based on the relationship between steady state creep rate and stress, the creep stress exponent of commercial pure titanium at room temperature is calculated to be 6.96, which also shows the reliability of extrapolated steady state creep rate. The activation energy of creep at moderate and low temperatures varies little with creep (鈮，

本文編號：2374464