(1. 湖南科技大學(xué)高溫耐磨材料及制備技術(shù)湖南省國防科技重點實驗室, 湘潭 411201；
2. 中南大學(xué)材料科學(xué)與工程學(xué)院，長沙 410083)
摘 要: 結(jié)合傳統(tǒng)擠壓與扭轉(zhuǎn)變形的特點提出正擠壓-扭轉(zhuǎn)復(fù)合變形方式，采用有限元軟件對其變形方式進(jìn)行數(shù)值模擬。研究扭轉(zhuǎn)角度對坯料變形過程中累積應(yīng)變的影響，并對經(jīng)過不同扭轉(zhuǎn)角度變形后坯料的等效應(yīng)變分布的不均勻程度進(jìn)行定量分析。根據(jù)正擠壓-扭轉(zhuǎn)復(fù)合變形的模擬結(jié)果，設(shè)計出較優(yōu)的模具結(jié)構(gòu)并進(jìn)行實驗研究。結(jié)果表明：正擠壓-扭轉(zhuǎn)復(fù)合變形可以顯著提高鎂合金變形過程的累積應(yīng)變，隨著扭轉(zhuǎn)角度的增大，累積應(yīng)變增大，但不均勻程度相對增加，最大等效應(yīng)變高達(dá)3.75。當(dāng)模具扭轉(zhuǎn)角為40°時，試樣可獲得較大的等效應(yīng)變和均勻的等效應(yīng)變分布。在復(fù)合變形后，AZ31鎂合金的晶粒尺寸由300 μm顯著細(xì)化至約6 μm。
關(guān)鍵字: AZ31鎂合金；有限元模擬；復(fù)合擠壓變形；等效應(yīng)變分布
（1. Hunan Provincial Key Defense Laboratory of High Temperature Wear-resisting Materials and
Preparation Technology, Hunan University of Science and Technology, Xiangtan 411201, China;
2. School of Materials Science and Engineering, Central South University, Changsha 410083, China）
Abstract:Combining the feature of traditional extrusion and torsional deformation, direct extrusion and torsional compound deformation was proposed, and numerical simulation of deformation process was investigated using finite element software. Effect of torsion angle on cumulative strain during the deformation process was studied, and the non-uniformity of the equivalent strain distribution after different torsion angle deformation was also analyzed quantitatively. According to the simulation results of direct extrusion and torsional deformation, reasonable die structure was designed, and experimental research was carried out. The results show that the direct extrusion and torsional compound deformation can significantly enhance the accumulation strain of deformed magnesium alloys, and the cumulative strain increases with the increase of torsional angle, the maximum equivalent strain can get up to 3.75, but the degree of nonuniformity increases relatively. The specimen can obtain larger and more uniform distribution of equivalent strain for torsion angle of 40°. After compound deformation, the grain size of AZ31 magnesium alloy can be significantly refined from 300 μm to about 6 μm.
Key words: AZ31 magnesium alloy; finite element simulation; compound extrusion; equivalent strain distribution
