(合肥工业大学 材料科学与工程学院，合肥 230009)
摘 要: 采用DEFORM-3D软件对纯钼粉末多孔烧结材料等径角挤压过程进行单道次三维有限元模拟和实验研究，获得变形过程中试样的应力、应变、致密行为等相关场量变化规律。模拟结果表明：等径角挤压工艺对粉末材料具有强烈的致密效果，整个变形过程可分为3个阶段，即初始变形、过渡变形及稳定变形；试样纵横截面上，等效应变均存在不均匀分布现象，靠近模具内角和上表面处试样所获应变较大，相对密度也较高。试样不同部位所处应力状态及应变速率分布状态的不一致是导致其应变分布不均匀的根本原因。单道次挤压实验结果与模拟结果具有较好的一致性，证明了所建立有限元模型的可靠性。
关键字: 粉末烧结材料；等径角挤压；数值模拟；显微组织
（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
