AZ31B鎂合金雙道次熱變形過(guò)程流變應(yīng)力特征模擬研究

AZ31B鎂合金雙道次熱變形過(guò)程流變應(yīng)力特征模擬研究Simulation of Flow Stress Characteristic During Two-stage Hot Deformation Process in AZ31B Magnesium Alloy

建立了一類鎂合金雙道次熱變形過(guò)程的二維元胞自動(dòng)機(jī)模型?？紤]到鎂合金具有六重對(duì)稱的密排六方晶體結(jié)構(gòu)，模型采用了六邊形元胞網(wǎng)格。另外，通過(guò)計(jì)算位錯(cuò)密度演變和設(shè)定晶粒形核長(zhǎng)大規(guī)則，模型將熱變形過(guò)程中動(dòng)態(tài)再結(jié)晶、靜態(tài)回復(fù)、靜態(tài)再結(jié)晶、亞動(dòng)態(tài)再結(jié)晶和晶粒長(zhǎng)大等單個(gè)物理過(guò)程耦合到一起。為了驗(yàn)證模型，將其應(yīng)用到AZ31B鎂合金單道次和雙道次熱壓縮過(guò)程。探討了不同變形溫度、應(yīng)變速率、道次間隔和預(yù)應(yīng)變對(duì)應(yīng)力-應(yīng)變曲線的影響。將計(jì)算結(jié)果和實(shí)驗(yàn)結(jié)果進(jìn)行了對(duì)比，吻合較好。

A 2-D CA model has been developed to simulate two-stage hot deformation processing of magnesium (Mg) alloy. Based on the fact that Mg has an HCP crystal structure with six-fold symmetry, the model employs hexagonal CA lattice. The physically-based model has integrated the effects of individual metallurgical phenomena related with the hot deformation, including dynamic recrystallization (DRX), static recovery, static recrystallization (SRX), meta-dynamic recrystallization (MDRX) and grain growth, etc. The model is validated by simulating single-stage and two-stage hot compression tests of AZ31B. The effects of temperature, strain rate, the interval and pre-strain on stress-strain curves are investigated. The calculated results are compared with the available experimental findings in AZ31B Mg alloy, and the simulated results agree well with the experimental results and theoretical models.

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