高溫塑性變形行為的熱壓縮模擬
(中南大學(xué) 材料科學(xué)與工程學(xué)院，長(zhǎng)沙 410083)
摘 要: 采用Gleeble−1500熱壓縮模擬試驗(yàn)機(jī)進(jìn)行壓縮實(shí)驗(yàn)，研究ZK60(0.9Y+0.3Nd)鎂合金在變形溫度623~773 K、應(yīng)變速率0.001~1 s−1的范圍內(nèi)的變形行為，計(jì)算應(yīng)力指數(shù)和變形激活能，并采用Zener-Hollomon參數(shù)法構(gòu)建合金高溫塑性變形的本構(gòu)關(guān)系。結(jié)果表明：在實(shí)驗(yàn)變形條件下，合金的真應(yīng)力—真應(yīng)變曲線為動(dòng)態(tài)再結(jié)晶型；在實(shí)驗(yàn)溫度范圍內(nèi)，應(yīng)力指數(shù)隨著變形溫度的升高而增大，變形激活能隨著變形溫度和應(yīng)變速率的增加而增大。對(duì)比ZK60合金，ZK60(0.9 Y+0.3Nd)合金的變形激活能提高38%。
關(guān)鍵字: 塑性變形；熱模擬；動(dòng)態(tài)再結(jié)晶；鎂合金
（School of Materials Science and Engineering, Central South University, Changsha 410083, China）
Abstract:The hot deformation behavior of ZK60(0.9Y+0.3Nd) magnesium alloy was investigated by hot compressive tests on Gleeble−1500 thermal simulation test machine in the temperatures range of 623−773 K and strain rate range of 0.001−1s−1. The stress exponent and the deformation activation energy at elevated temperatures (623−773 K) were calculated. The constitutive equation of the plastic deformation of ZK60(0.9Y+0.3Nd) alloy at elevated temperatures (623−773 K) was obtained by introducing Zener-Hollomon parameter. The results show that the true stress—strain curves of the alloy have dynamic recrystallization character under the present deformation conditions. In the temperature range of 623−773 K, the stress exponent increases with the increase of deformation temperature. The deformation activation energy changes with the increase of deformation temperature and strain rate. Compared with ZK60 alloy, the deformation activation energy of ZK60(0.9Y+0.3Nd) alloy increases by 38%.
Key words: plastic deformation; thermal simulation; dynamic recrystallization; magnesium alloy
