(1. 中南大學(xué) 材料科學(xué)與工程學(xué)院，長沙 410083；
2. 中南大學(xué) 有色金屬材料科學(xué)與工程教育部重點實驗室，長沙 410083)
摘 要: 在溫度為723 K、應(yīng)變速度為3×10−3 s−1的條件下，對Mg-Y及AZ31鎂合金擠壓棒材進(jìn)行單向壓縮變形，利用OM、SEM和EBSD觀察、分析Y對擠壓棒材動態(tài)再結(jié)晶和微觀織構(gòu)的影響。結(jié)果表明：AZ31鎂合金在真應(yīng)變ε=0.2時發(fā)生明顯的動態(tài)再結(jié)晶，在ε=0.5時，動態(tài)再結(jié)晶晶粒的體積分?jǐn)?shù)高達(dá)80%以上；而Mg-Y合金在真應(yīng)變ε=0.4時，動態(tài)再結(jié)晶體積分?jǐn)?shù)尚不足10%，Y對鎂合金動態(tài)再結(jié)晶有顯著的阻礙作用；AZ31鎂合金變形時，幾乎所有晶粒的基面趨向于由變形前平行于壓縮方向轉(zhuǎn)至垂直于壓縮方向，導(dǎo)致基面織構(gòu)在ε=1.2時發(fā)生近90°的轉(zhuǎn)動；Mg-Y合金則只有小部分晶粒發(fā)生轉(zhuǎn)動，轉(zhuǎn)動所形成的擇優(yōu)取向在動態(tài)再結(jié)晶后顯著弱化，并導(dǎo)致取向分布更加隨機；Y的添加可導(dǎo)致鎂合金基面織構(gòu)在動態(tài)再結(jié)晶后顯著弱化。
關(guān)鍵字: 鎂合金；釔；高溫變形；動態(tài)再結(jié)晶；微觀織構(gòu)
Mg-Y and AZ31 Mg alloy during hot deformation
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education,
Central South University, Changsha 410083, China）
Abstract:The effects of Y on the dynamic recrystallization (DRX) and microtexture evolution of hot deformed Mg alloy were studied by optical, SEM and EBSD microscopy. For this purpose, AZ31 and Mg-Y alloy bars were compressed at strain rate of 3×10−3 s−1 and at temperature of 723 K. The results show that DRX frequently takes place in AZ31 Mg alloy just after being compressed to strained ε=0.2 and the volume fraction of DRX grains is more than 80% after further being compressed to strained 0.5. Whereas alloying by Y retarded DRX, the fraction of DRX in Mg-Y alloy is less than 10% even at the strain of 0.4. In AZ31 Mg alloy, the alignment of the basal planes initially parallel to the compression direction is rotated gradually by compression and approaches perpendicular to the compression direction in high strain and the basal texture is rotated by about 90º at the strain of 1.2. But in Mg-Y alloy, only a few grains rotate to be perpendicular to the compression direction with increasing strain. The basal texture caused by the rotated grains is significantly weakened and the orientation distribution becomes more random after DRX. The basal texture of Mg alloy can be significantly weakened after DRX by the addition of Y.
Key words: magnesium alloy; yttrium; hot deformation; dynamic recrystallization; microtexture
