(1. 東北大學 材料與冶金學院，沈陽 110004；
2. 東北大學 軋制技術(shù)及連軋自動化國家重點實驗室，沈陽 110004)
摘 要: 通過數(shù)值模擬，分析AZ31鎂合金在連續(xù)流變擠壓成形過程中的溫度場與流場分布規(guī)律。結(jié)果表明： 輥−靴型腔內(nèi)合金的溫度從入口至出口逐漸降低，合金等溫線向工作輥偏移；隨著澆注溫度的降低，輥−靴型腔內(nèi)半固態(tài)區(qū)間逐漸增大；為了獲得優(yōu)良的半固態(tài)金屬漿料，確定澆注溫度為710~770 ℃；合金在輥−靴型腔內(nèi)層流運動時，越靠近工作輥內(nèi)表面，合金的運動速度越快；隨著擠壓模具擴展角的增大，擠壓模具出口型材寬度上中心與兩側(cè)邊部合金的溫度差減小；半固態(tài)合金進入模具后呈輻射狀逐層向前推進填充模具擴展腔，最后再逐漸向模具出口合攏；為了改善模腔內(nèi)金屬流動速度的不均勻性，擴展角以45˚為宜。
關(guān)鍵字: 鎂合金；AZ31合金；半固態(tài)；連續(xù)擠壓；流變擠壓；數(shù)值模擬；溫度；速度
AZ31 alloy
（1. School of Materials and Metallurgy, Northeastern University, Shenyang 110004, China;
2. State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang 110004, China）
Abstract:Through numerical simulation, the temperature and velocity distributions during the continuous rheo-extrusion process of AZ31 alloy were analyzed. The results show that the temperature of the alloy gradually decreases from the casting mouth to the exit in the roll-shoe gap, and the isothermal line deviates from the shoe side to the roll side. The semi-solid region in the roll-shoe gap increases with decreasing casting temperature. In order to prepare a good quality semi-solid slurry, the casting temperature of 710−770 ℃ is suggested. The alloy flows in the roll-shoe gap with a laminar pattern and the velocity near the roll is larger than that near the shoe. The temperature difference between the center and the side of the product at the deformation zone decreases with the increase of extending angle; the semi-solid alloy gradually fills the extending mould with a laminar pattern, then, it gathers at the exit of deformation mould. In order to modify the inhomogeneous flow of the alloy in the mould cavity, the extending angle is suggested to be 45˚.
Key words: magnesium alloy; AZ31 alloy; semi-solid; continuous extrusion; rheo-extrusion; numerical simulation; temperature; velocity
