(合肥工業(yè)大學(xué) 材料科學(xué)與工程學(xué)院，合肥 230009)
摘 要: 采用DEFORM-3D軟件對純鉬粉末多孔燒結(jié)材料等徑角擠壓過程進(jìn)行單道次三維有限元模擬和實(shí)驗(yàn)研究，獲得變形過程中試樣的應(yīng)力、應(yīng)變、致密行為等相關(guān)場量變化規(guī)律。模擬結(jié)果表明：等徑角擠壓工藝對粉末材料具有強(qiáng)烈的致密效果，整個(gè)變形過程可分為3個(gè)階段，即初始變形、過渡變形及穩(wěn)定變形；試樣縱橫截面上，等效應(yīng)變均存在不均勻分布現(xiàn)象，靠近模具內(nèi)角和上表面處試樣所獲應(yīng)變較大，相對密度也較高。試樣不同部位所處應(yīng)力狀態(tài)及應(yīng)變速率分布狀態(tài)的不一致是導(dǎo)致其應(yīng)變分布不均勻的根本原因。單道次擠壓實(shí)驗(yàn)結(jié)果與模擬結(jié)果具有較好的一致性，證明了所建立有限元模型的可靠性。
關(guān)鍵字: 粉末燒結(jié)材料；等徑角擠壓；數(shù)值模擬；顯微組織
（School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009, China）
Abstract:Three-dimensional finite element model was used to analyze the deformation behavior of pure molybdenum powder sintered material with porosities during a single pass of equal channel angular pressing (ECAP).The distributions of effective strain, effective stress and relative density of the sample during ECAP processing were obtained. The simulation results indicate that ECAP is an effective technique to densify powder materials and the whole deformation process could be divided into three stages: initial deformation, transitional deformation and steady deformation. The inhomogeneous deformations exist in the transverse plane and longitudinal plane of the sample, and the effective strain and relative density in the inner side and on the top of the sample are much larger than those at other positions. This inhomogeneity is attributed to the fact that the stress state and strain rate at different positions of the sample are different. In addition, the experimental results have good consistency with the simulation ones, which shows the reliability of established finite element model.
Key words: powder sintered material; equal channel angular pressing; numerical simulation; microstructure
