(1. 上海交通大學(xué) 輕合金精密成型國家工程研究中心，上海 200030；2. 長岡技術(shù)科學(xué)大學(xué) 機(jī)械系，新潟 940-2188，日本)
摘 要: 根據(jù)元胞自動機(jī)的模擬結(jié)果研究了AZ91合金熱壓縮過程中的再結(jié)晶動力學(xué)。結(jié)果表明，隨著應(yīng)變量增加，再結(jié)晶分?jǐn)?shù)增加；隨著變形溫度升高，再結(jié)晶速率加快。穩(wěn)態(tài)組織的平均晶粒尺寸與Zener-Hollomom參數(shù)成反比，指數(shù)為−0.05。壓縮過程中，所有晶粒的平均尺寸迅速下降后緩慢減小至穩(wěn)態(tài)值，原始晶粒平均尺寸呈線性減小為0，再結(jié)晶晶粒平均尺寸先增加至某一峰值后緩慢下降至穩(wěn)態(tài)值。基體內(nèi)同時存在的多次再結(jié)晶現(xiàn)象使得流變曲線呈單峰特征。
關(guān)鍵字: AZ91合金；元胞自動機(jī)；動態(tài)再結(jié)晶；動力學(xué)
（1. National Engineering Research Center of Light Alloy Net Forming,Shanghai Jiao Tong University, Shanghai 200030, China;2. Department of Mechanical Engineering, Nagaoka University of Technology, Niigata 940-2188, Japan）
Abstract:The kinetics of dynamic recrystallization (DRX) during the hot compression process of AZ91 magnesium alloy was investigated based on the cellular automata simulation. The simulation results indicate that the fraction of DRX increases with strain increase and the velocity of DRX increases with process temperature increase. The relationship between the average grain size in the final microstructure and Zener-Hollomom parameter follows an inverse power law with the exponent of −0.05. During a compression process, the average size of total grains decreases rapidly in an initial stage, and then slowly to a steady value; the average size of initial grains decreases linearly to zero; the average size of recrystallized grains increases to a peak value and then decreases slowly to a steady value. Multi-cycle recrystallizaiton occurs concurrently in the matrix, resulting in a single peak on each flow curve.
Key words: AZ91 alloy; cellular automata; dynamic recrystallizaiton; kinetics
