(1. 重慶交通大學(xué)交通土建工程材料國(guó)家地方聯(lián)合工程實(shí)驗(yàn)室，重慶 400074；
2. 重慶大學(xué)材料科學(xué)與工程學(xué)院，重慶 400044)
摘 要: 沿?zé)彳埻嘶饝B(tài)AZ31鎂合金軋制方向進(jìn)行室溫動(dòng)態(tài)塑性變形，采用場(chǎng)發(fā)射掃描電子顯微鏡研究 孿生的變體類型及結(jié)構(gòu)特征。結(jié)果表明：在 孿生機(jī)制主導(dǎo)塑性變形的初級(jí)階段(ε＜8%)，AZ31鎂合金中大部分晶粒內(nèi)部?jī)H產(chǎn)生一種 孿生變體或變體對(duì)，所以孿晶結(jié)構(gòu)呈彼此平行狀，將晶粒分割成片層組織；這種片層組織的厚度隨著應(yīng)變量的增加而減小，從5.55μm減小到2.49μm；少數(shù)晶粒形核產(chǎn)生不同的 孿生變體，且這種晶粒的數(shù)量隨著塑性變形量的增大而增加；當(dāng)ε＞8%，孿生體積分?jǐn)?shù)接近飽和，位錯(cuò)滑移成為鎂合金主要的變形機(jī)制。
關(guān)鍵字: 鎂合金；動(dòng)態(tài)塑性變形；孿生變體；變形機(jī)制
（1. National and Local Joint Engineering Laboratory of Traffic Civil Engineering Materials,
Chongqing Jiaotong University, Chongqing 400074, China;
2. School of Materials Science and Engineering, Chongqing University, Chongqing 400044, China）
Abstract:Both variant type and structure characteristic of twinning in the as-rolled AZ31 magnesium alloy subjected to dynamic plastic deformation at room temperature along the rolling direction were investigated. The results show that at the stage of twinning-dominated deformation (ε<8%), mostly a twin variant or a twin variant pair is activated in the grain of AZ31 magnesium alloy, leading to a paralleltwin lamellar structure. The lamellar thickness decreases significantly from 5.55μm to 2.49μm with increasing the strain. Meanwhile, different variant pairs also generate in some grains, and the number of these grains increases with increasing the plastic strain. When the plastic strain is greater than 8%, the volume fraction of twins almost saturates and dislocation slips dominate the later deformation.
Key words: magnesium alloy; dynamic plastic deformation; twinning variant; deformation mechanism
