对AISI-4140材料的等通道转角扭挤过程进行数值模拟,将扭转角β、背压P、摩擦因子μ和挤压速度v作为挤压工艺参数,以平均等效塑性应变εm、平均等效塑性应力σm、最大损伤值δmax作为优化设计目标。运用追踪点法和灰色系统理论的灰色关联度优化工艺参数,最终使设计目标值达到εmmax、σmmax、δmmianx。结果表明,在施加背压的条件下,ECAPTE工艺使变形材料迅速地形变累积,最大损伤值显著地减小,使剧烈塑性变形材料组织的晶粒获得显著细化。 The isotropic channel twist process of AISI-4140 was numerically simulated. The twist angle β, back pressure P, friction factor μ and extrusion speed v were used as the extrusion process parameters. The average equivalent plastic strain εm was averaged Plastic stress σm, the maximum damage δmax as the optimal design goals. The gray relational degree of tracking point method and gray system theory is used to optimize the process parameters, finally the designed target value reaches εmmax, σmmax, δmmianx. The results show that under the condition of back pressure, the ECAPTE process causes the deformation of the deformed material to rapidly deform and accumulate, the maximum damage value is significantly reduced, and the grains of the material with severe plastic deformation are remarkably refined.