(1. 東北大學(xué) 材料與冶金學(xué)院，沈陽 110004；
2. 東北大學(xué) 軋制技術(shù)及連軋自動化國家重點實驗室，沈陽110004)
摘 要: 利用波浪形傾斜板振動技術(shù)制備AZ31鎂合金半固態(tài)坯料，獲得較為理想的球形或近球形晶粒組織。結(jié)果表明：隨二次加熱溫度的升高和保溫時間的延長，半固態(tài)組織中的液相體積分?jǐn)?shù)增大, 固相逐漸長大并球化；AZ31鎂合金580 ℃和610 ℃時二次加熱組織均不適合半固態(tài)觸變成形；適合觸變成形的二次加熱最優(yōu)工藝為590 ℃保溫40～60 min、或者600 ℃保溫30 min；此條件下獲得的平均晶粒直徑為58～61 μm，固相率為87%(體積分?jǐn)?shù))左右。晶格擴散機制對二次加熱原子擴散起主導(dǎo)作用，是造成合金固相顆粒尺寸變化的根本原因；固液界面張力是造成顆粒形狀球形或近球形變化的重要原因。
關(guān)鍵字: AZ31鎂合金；半固態(tài)；傾斜板；二次加熱；顯微組織
semisolid AZ31 magnesium alloy during reheating process
（1. School of Materials and Metallurgy, Northeastern University, Shenyang 110004, China;
2. The State Key Laboratory of Rolling and Automation, Shenyang 110004, China）
Abstract:AZ31 magnesium semisolid billets were prepared by a self-designed wavelike vibration sloping plate device, and an ideal globular or near-globular microstructure can be obtained by wavelike vibration sloping plate technique. The results show that, with the increase of reheating temperature and the prolongation of holding time, the liquid fraction in semisolid microstructure increases, and the solid phase grows gradually and spheroidises. The reheating microstructures at 580 ℃ and 610 ℃ are not suitable for thixoforming. The optimum reheating process parameters suitable for thixoforming are 590 ℃ for 40−60min or 600 ℃ for 30 min, under which the average grain diameter is 58−61 μm and solid fraction is about 87%. The lattice diffusion resulting in the variation of grain size is the dominant atomic diffusion mechanism of reheating. The solid-liquid interfacial tension results in the variation of globular or near-globular shape.
Key words: AZ31 magnesium alloy; semisolid; sloping plate; reheating; microstructure
