(1. 湖南科技大學(xué) 難加工材料高效精密加工湖南省重點(diǎn)實(shí)驗(yàn)室，湘潭 411201； 2. 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(diǎn)實(shí)驗(yàn)室，湘潭 411201； 3. 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)擠壓與彎曲剪切變形的特點(diǎn)提出一種棒-板正擠壓-彎曲剪切復(fù)合連續(xù)變形新工藝，該工藝既可顯著細(xì)化晶粒又可以弱化織構(gòu)，極大地改善鎂合金的綜合力學(xué)性能。通過分析該復(fù)合變形方式的特點(diǎn)，建立了總擠壓力數(shù)學(xué)模型，對正擠壓-彎曲剪切復(fù)合成形所需的擠壓力進(jìn)行了系統(tǒng)、完整、準(zhǔn)確的表征。根據(jù)各分區(qū)的變形特點(diǎn)，把實(shí)際的正擠壓模型類比成等效面積的圓棒擠壓模型，并引入形狀復(fù)雜系數(shù)，利用上界法得出各分區(qū)的擠壓力解析表達(dá)式，基于有限元數(shù)值模擬對形狀復(fù)雜系數(shù)進(jìn)行分析求解。最后通過與實(shí)驗(yàn)結(jié)果的比較得出該模型計(jì)算的結(jié)果與實(shí)際值的誤差在5%的范圍內(nèi)，滿足工程計(jì)算要求。
關(guān)鍵字: 鎂合金；正擠壓-彎曲剪切復(fù)合變形；顯微組織；力學(xué)性能；形狀復(fù)雜系數(shù)；擠壓力
（1. Hunan Provincial Key Laboratory of High Efficiency and Precision Machining of Difficult-to-cut Material, Hunan University of Science and Technology, Xiangtan 411201, China; 2. Hunan Provincial Key Defense Laboratory of High Temperature Wear-resisting Materials and Preparation Technology, Hunan University of Science and Technology, Xiangtan 411201, China; 3. School of Materials Science and Engineering, Central South University, Changsha 410083, China）
Abstract:Combining with the features of traditional extrusion and bending shear deformation, a new technology of rod-plate direct extrusion and bending shear compound deformation was proposed, which can not only significantly refine the grain size, but also weaken the texture, thus improve the mechanical properties of Mg alloys greatly. Based on the analysis of the compound deformation features, the mathematical model of the total extrusion load was established, The extrusion force required for direct extrusion bending shear compound deformation is systematically, completely and accurately characterized. According to the deformation features of each zone, the actual direct extrusion model can be analogized to the equivalent area of extruded bar model, and a complex shape coefficient is introduced. The upper bounding method is used to get analytical expression of the extrusion force of each zone. The complex coefficient of shape is analyzed and solved based on the finite element numerical simulation. Finally, the research result shows that the error range between calculated value from the mathematical model and the actual value is below 5%, which can satisfy the engineering calculation requirement.
Key words: Mg alloys; direct extrusion-bending shear compound deformation; microstructure; mechanical properties; complex shape coefficient; extrusion load
