(1. 中南大學(xué) 材料科學(xué)與工程學(xué)院，長沙 410083；
2. 中南大學(xué) 有色金屬材料與工程教育部重點(diǎn)實(shí)驗(yàn)室，長沙 410083；
3. Department of Chemical and Materials Engineering, University of Auckland, Auckland 1102, New Zealand)
摘 要: 采用Gleeble−1500熱模擬機(jī)對ZK60鎂合金在溫度為200~400 ℃、應(yīng)變速率為0.001~10 s−1、最大變形量為60%的條件下進(jìn)行恒應(yīng)變速率高溫壓縮實(shí)驗(yàn)，研究高溫變形過程中合金的動態(tài)再結(jié)晶行為；采用EM模型描述合金的動態(tài)回復(fù)曲線，以此為基礎(chǔ)，得出ZK60合金熱壓縮過程中的動態(tài)再結(jié)晶動力學(xué)Avrami方程。利用有限元模擬合金熱壓縮過程中的動態(tài)再結(jié)晶。結(jié)果表明：ZK60合金熱壓縮過程中由于存在動態(tài)再結(jié)晶的軟化作用，流變應(yīng)力達(dá)到峰值后逐漸減小，并最終達(dá)到穩(wěn)態(tài)；隨著變形量的增加和變形溫度的升高，動態(tài)再結(jié)晶體積分?jǐn)?shù)增加，合金變形更加均勻；隨著應(yīng)變速率的增加，動態(tài)再結(jié)晶分?jǐn)?shù)有所減小，且變形也更不均勻。
關(guān)鍵字: ZK60 鎂合金；熱變形；流變應(yīng)力；動態(tài)再結(jié)晶；動力學(xué)
ZK60 magnesium alloy during hot deformation
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education,
Central South University, Changsha 410083, China;
3. Department of Chemical and Materials Engineering, University of Auckland, Auckland 1102, New Zealand）
Abstract:The kinetics of dynamic recrystallization of ZK60 magnesium alloy was investigated by compression tests at temperature of 200−400 ℃ and strain rate of 0.001−10 s−1. The flow stress curves considering only dynamic recovery was described by EM model. Based on EM model, the kinetics of dynamic recrystallization of ZK60 alloy was modeled by an Avrami-type equation. The finite element simulations were utilized to simulate the recrystallization process of ZK60 alloy during hot compression. The results show that, due to the effect of dynamic recovery, the flow stress increases to a peak value and subsequently decreases to steady state. Both the volume fraction of dynamic recrystallization and the deformation homogeneity increase with the increase of the plastic strain and deformation temperature, while decrease with the increase of strain rate.
Key words: ZK60 magnesium alloy; hot deformation; flow stress; dynamic recrystallization; kinetics
