(1. 北京科技大學(xué) 材料科學(xué)與工程學(xué)院，北京 100083；
2. 遼寧科技大學(xué) 材料科學(xué)與工程學(xué)院，鞍山 114051)
摘 要: 在250~ 400 ℃溫度范圍內(nèi)以恒溫、恒應(yīng)變速率(10-3 和10-2 s-1) 對(duì)鑄軋AZ31 鎂合金進(jìn)行拉伸實(shí)驗(yàn)，在不同應(yīng)變下研究溫度和應(yīng)變速率對(duì)動(dòng)態(tài)再結(jié)晶的影響，探討二相粒子對(duì)動(dòng)態(tài)再結(jié)晶的影響，并分析動(dòng)態(tài)再結(jié)晶機(jī)制。結(jié)果表明：當(dāng)應(yīng)變相同時(shí)，再結(jié)晶晶粒尺寸隨溫度升高而增大。中溫區(qū)(200~300 ℃)動(dòng)態(tài)再結(jié)晶的主導(dǎo)機(jī)制為連續(xù)動(dòng)態(tài)再結(jié)晶，高溫區(qū)(300 ℃以上)動(dòng)態(tài)再結(jié)晶的主導(dǎo)機(jī)制為不連續(xù)動(dòng)態(tài)再結(jié)晶。變形過(guò)程中破碎的Mg17Al12相粒子及釘扎在晶界處的(Al,Mn)相粒子可提高動(dòng)態(tài)再結(jié)晶的形核率。在350 ℃下，當(dāng)應(yīng)變速率由10-3 s-1 升高到10-2 s-1 時(shí)，晶粒尺寸逐漸減小，且出現(xiàn)孿生再結(jié)晶。
關(guān)鍵字: AZ31 鎂合金；鑄軋；動(dòng)態(tài)再結(jié)晶
（1. School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China;
2. School of Materials Science and Engineering, University of Science and Technology Liaoning, Anshan 114051, China）
Abstract:Tensile tests were conducted for a twin-roll cast AZ31 alloy under constant temperatures (250-400 ℃) and constant strain rates of 10-3 and 10-2 s-1, aimed to study the effects of temperature and strain rate on dynamic recrystallization at different strains, to explore the effects of the second phase particles on dynamic recrystallization, and to analyze the mechanisms of dynamic recrystallization. The results show that the grain size of the recrystallized grains increases with temperature under the same strain. The continuous dynamic recrystallization dominates at the intermediate temperature range (200-300 ℃), while the discontinuous dynamic recrystallization dominates at high temperatures (over 300 ℃) . The fractured Mg17Al12 particles and the (Al, Mn) phase particles pinning at grain boundary can improve the nucleation rate of dynamic recrystallization. When the strain rate increases from 10-3 s-1 to 10-2 s-1 at 350 ℃, the grain size gradually decreases, and the twin recrystallizaiton occurs.
Key words: AZ31 magnesium alloy; twin-roll cast; dynamic recrystallization
