(1. 沈陽理工大學(xué) 材料科學(xué)與工程學(xué)院，沈陽 110159；
2. 東北財經(jīng)大學(xué) 金融學(xué)院，大連 116025)
摘 要: 在變形溫度為260~410 ℃、應(yīng)變速率為0.001~10 s-1條件下，對AZ80鎂合金進行熱拉伸實驗，測試AZ80鎂合金的真應(yīng)力-真應(yīng)變曲線；依據(jù)Arrhenius本構(gòu)方程形式，確定AZ80鎂合金熱變形過程的本構(gòu)關(guān)系模型；提出一種新的加工硬化率方法，當(dāng)加工硬化率函數(shù)對應(yīng)變(ε)求一階導(dǎo)數(shù)后的函數(shù)取最小值時所對應(yīng)的應(yīng)變值，即為臨界應(yīng)變(εc)。采用新的加工硬化率方法，確定AZ80鎂合金在不同變形條件下動態(tài)再結(jié)晶的臨界應(yīng)變和臨界應(yīng)力；研究熱變形工藝參數(shù)對臨界應(yīng)變和臨界應(yīng)力的影響規(guī)律；確定AZ80鎂合金熱變形過程中的臨界應(yīng)變、臨界應(yīng)力、穩(wěn)定應(yīng)變與Z參數(shù)的關(guān)系模型。模型計算結(jié)果與Sellars模型結(jié)果相吻合。
關(guān)鍵字: AZ80鎂合金；加工硬化率；動態(tài)再結(jié)晶；臨界條件
（1. School of Materials Science and Engineering, Shenyang Ligong University, Shenyang 110159, China;
2. Dongbei University of Finance and Economics, Dalian 116025, China）
Abstract:The curves of true stress-strain of AZ80 magnesium alloy are tested by thermal tensile method, which the ranges of temperature is from 260 to 410 oC and strain rates is from 0.001 to 10 s-1. According to the Arrhenius equation，the constitutive model of AZ80 magnesium alloy at thermal deformation was determined. A new work hardening rate method was proposed. When the derivative of work hardening rate function takes minimum value, the corresponding strain is the critical strain(εc). The work hardening rate method was used to determine the critical strain and critical stress of dynamic recrystallization under different deformation. The relation model of critical strain and critical stress and steady strain with Zener-Hollomn parameters (Z) were established. Calculation results of the critical strain model are in good agreement with that of Sellar’s model.
Key words: AZ80 magnesium alloy; working hardening rate; dynamic recrystallization; critical condition
