(中南大學(xué) 材料科學(xué)與工程學(xué)院，長(zhǎng)沙 410083)
摘 要: 采用Geeble−1500熱模擬實(shí)驗(yàn)機(jī)測(cè)試了高強(qiáng)耐熱Mg-6Gd-3Y-0.5Zr合金在變形溫度為300~500 ℃、應(yīng)變速率為10−3~1 s−1下的流變力學(xué)行為，采用掃描電子顯微鏡對(duì)其微觀(guān)組織進(jìn)行觀(guān)察，分析了冪函數(shù)(PI)、指數(shù)函數(shù)(EI)和雙曲正弦函數(shù)(SI)半經(jīng)驗(yàn)本構(gòu)方程對(duì)該合金變形行為擬合的適用性。結(jié)果表明：EI擬合實(shí)驗(yàn)結(jié)果精度大于PI和SI的，即使對(duì)SI函數(shù)中材料常數(shù) 進(jìn)行一定優(yōu)化處理得到SIO函數(shù)的擬合精度，也與EI函數(shù)十分接近。合金中高溫耐熱相提高合金高溫下的強(qiáng)度是EI擬合優(yōu)于PI和SI的原因。
關(guān)鍵字: Mg-Gd-Y-Zr合金；熱壓縮變形；本構(gòu)方程；材料常數(shù)優(yōu)化
Mg-Gd-Y-Zr alloy
（School of Materials Science and Engineering, Central South University, Changsha 410083, China）
Abstract:Three kinds of constitutive equations, power law (PI), expression law (EI) and sine hyperbolic law (SI) were used to analyze the flow behavior of the Mg-6Gd-3Y-0.5Zr alloy after compression at temperatures of 300−500 ℃ and strain rates of 10−3−1 s−1 by using Geeble−1500 test machine. The microstructures were studied using scanning electron microscope (SEM). The results show that EI fits the experimental results better than PI and SI. And even, the sine hyperbolic law with the optimization of material parameter (SIO) exhibits the close precision to EI. The precipitated heat-resisting phase after compression is the reason for EI better fitting than PI and SI.
Key words: Mg-Gd-Y-Zr alloy; hot compression deformation; constitutive equation; material parameter optimization
