(東北大學(xué) 材料科學(xué)與工程學(xué)院 材料各向異性與織構(gòu)教育部重點(diǎn)實(shí)驗(yàn)室，沈陽 110004)
摘 要: 建立了一個(gè)模擬外應(yīng)力作用下AZ31鎂合金在高溫退火過程中晶粒長大和織構(gòu)演化的三維相場(chǎng)模型。通過3個(gè)歐拉角構(gòu)成的歐拉空間表達(dá)晶體學(xué)取向，賦予有序化參數(shù)以晶體學(xué)取向的物理意義。由于鎂合金晶體結(jié)構(gòu)為密排六方結(jié)構(gòu)，不同晶體學(xué)方向存在彈性各向異性，根據(jù)每個(gè)取向晶粒的(0001)面相對(duì)于外應(yīng)力方向的角度旋轉(zhuǎn)剛度矩陣，得到不同取向晶粒對(duì)應(yīng)的剛度矩陣，從而計(jì)算出外應(yīng)力對(duì)不同取向晶粒做的功。結(jié)果表明：將模擬結(jié)果與已有的實(shí)驗(yàn)結(jié)果進(jìn)行了對(duì)比分析，織構(gòu)模擬結(jié)果與實(shí)驗(yàn)觀察到的織構(gòu)相一致；外應(yīng)力的增加會(huì)使晶粒長大速率加快，當(dāng)外應(yīng)力大于600 MPa時(shí)，可能會(huì)導(dǎo)致晶粒的異常長大；此外，當(dāng)壓應(yīng)力大于400 MPa時(shí)，AZ31鎂合金中會(huì)產(chǎn)生á0001？晶向平行于外應(yīng)力方向的基面織構(gòu)。
關(guān)鍵字: 鎂合金；相場(chǎng)法；外應(yīng)力；晶粒長大；織構(gòu)
（Key Laboratory for Anisotropy and Texture of Materials, Ministry of Education, School of Materials and Engineering, Northeastern University, Shenyang 110089, China）
Abstract:A 3D phase-field model was established to investigate the effect of applied stress on grain growth and texture evolution in AZ31 magnesium alloy at elevated temperatures. The order parameters were given a physical meaning of lattice orientation of grains represented by three angles in spatial coordinates. The stiffness tensor for different grains was suggested different because of elastic anisotropy of the magnesium lattice by transforming the standard stiffness tensor with different degrees of the (0001) plane angle with respect to the direction of applied stress so that different grains contributed different amounts of work under applied stress. The results reveal that the simulation results are explained using the limited existing experimental data, and the texture results are in good agreement with the experimental observation. The grain-growth rate increases with the applied stress, which may lead to abnormal grain growth when the stress is greater than 600 MPa. Moreover, the applied stress will also result in an intensive texture of the á0001？ axis parallel to the direction of compressive stress when the applied stress is greater than 400 MPa.
Key words: magnesium alloy; phase-field simulation; applied stress; grain growth; texture
