(1. 中南大學(xué) 材料科學(xué)與工程學(xué)院，長沙 410083；
2. 中鋁洛陽銅業(yè)有限公司，洛陽 471039)
摘 要: 利用金相顯微鏡、透射電子顯微鏡對AZ31B鎂合金鑄軋板坯的微觀組織進(jìn)行研究。結(jié)果表明：鑄軋AZ31B鎂合金板坯主要由α-Mg基體、枝晶間Mg17Al12共晶體和彌散分布的細(xì)小析出相組成，鑄軋對晶粒的細(xì)化效果不明顯；板坯在鑄軋過程中經(jīng)歷一定的塑性變形，且變形多分布于板材表層；塑性變形在合金中產(chǎn)生大量的位錯及位錯胞的同時，也產(chǎn)生一定數(shù)量的孿晶；經(jīng)孿生改變晶體取向后的晶粒會在適合的條件下發(fā)生滑移變形，孿生和滑移的協(xié)同作用使孿晶和位錯共存、孿晶中位錯的產(chǎn)生和孿晶的變形；鑄軋時的塑性變形和高溫還導(dǎo)致回復(fù)和再結(jié)晶的發(fā)生。
關(guān)鍵字: AZ31B合金；雙輥鑄軋；孿生；位錯滑移
（1. School of Materials Science and Engineering, Central South University, Changsha 410083,China;
2. Chinalco Luoyang Copper Co. Ltd, Luoyang 471039, China）
Abstract:The microstructures of AZ31B magnesium alloy twin-roll cast sheet were studied by metallographic microscope and TEM. The results show that the sheet is made up of α-Mg matrix, interdendritic Mg17Al12 eutectic and some dispersive fine precipitates. Sheet undergoes biggish plastic deformation, and the deformation distributes more near sheet surface than interior. A mass of dislocations and dislocation cells form during plastic deformation while some twins form simultaneously. After twining, the grain orientations change, and then they will slip on suitable condition. This process leads the formation of dislocations in twins and deformation of twins. The recovery and recrystallization reduce during twin-roll casting because of the plastic deformation and high temperature.
Key words: AZ31B alloy; twin-roll cast; twins; dislocations slipping
