(大連理工大學(xué) 材料科學(xué)與工程學(xué)院，大連 116024)
摘 要: 對AZ31鎂合金熱擠壓棒材在室溫下沿擠壓方向分別進行了應(yīng)變?yōu)?%、6%、10%的單向壓縮實驗。利用OM、XRD和EBSD等技術(shù)研究了不同壓縮應(yīng)變量下的顯微組織、織構(gòu)及應(yīng)變硬化的演變特征。結(jié)果表明：具有{0002}纖維織構(gòu)的熱擠壓態(tài)AZ31鎂合金沿著擠出方向壓縮時，產(chǎn)生顯著的應(yīng)變硬化效應(yīng)。其塑性變形可大致分為3個階段：初始階段主要發(fā)生{1012}拉伸孿生，表現(xiàn)為較低的應(yīng)變硬化速率和應(yīng)變硬化速率的急劇減小；隨著壓縮應(yīng)變量的增加，孿晶界逐漸擴展，直至部分晶粒發(fā)生完全孿生，基面織構(gòu)強度逐漸增強；拉伸孿晶生長所造成的強{0002}基面織構(gòu)是產(chǎn)生高應(yīng)變硬化速率的主要原因；應(yīng)變硬化速率第Ⅱ~Ⅲ階段的轉(zhuǎn)折點大致與拉伸孿晶的生長停滯相對應(yīng)。
關(guān)鍵字: AZ31鎂合金；拉伸孿生；滑移；壓縮變形；孿晶界
（School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024, China）
Abstract:Uniaxial compression tests were carried out on an as-extruded AZ31 magnesium alloy along extrusion direction at the strain of 3%, 6% and 10%, respectively, at room temperature. The evolution of microstructures, textures and strain hardening behavior were examined by OM, XRD and EBSD. The results show that the present as-extruded magnesium alloy with {0002} fiber texture exhibits distinct three plastic deformation stages. {1012} tension twinning takes place at the first stage of the plastic deformation, which results in the low strain hardening rate and rapid decrease in strain hardening rate. With increasing the compressive strain, {1012} twin boundaries gradually extend until some grains are entirely consumed by the twinning extension, which results in the strong basal texture. The increasing high strain hardening rate are mainly attributed to the formation of strong basal texture. The deformation transition from stage Ⅱ to stage Ⅲ roughly corresponds to the stop of {1012} twin extending.
Key words: AZ31 magnesium alloy; tension twining; slip; compressing deformation; twinning grain boundary
