新型等通道球形转角膨胀挤压过程模拟与实验验证

Simulation and experimental validations of novel process entitled equal channel angular expansion extrusion with spherical cavity

将"球形分流"和"膨胀挤压"概念引入传统ECAP技术,提出一种新型等通道球形转角膨胀挤压(ECAEE-SC)工艺。采用有限元模拟和实验验证的方法研究ECAEE-SC过程中工业纯铝的塑性变形行为。结果表明:ECAEE-SC工艺具有复合剧烈塑性变形的效果,球形转角和膨胀通道为两个主要变形区域;挤压过程中材料处于理想的压应力状态,坯料单道次ECAEE-SC变形累积等效应变量约为3.5,整体变形均匀性良好,挤压效率大幅提高。挤压实验与有限元模拟结果相一致,挤出坯料外形完整且宏观无裂纹,坯料显微硬度平均值从初始36.6HV增加至70.2 HV,力学性能得到显著改善。

The concepts of "spherical split flow" and "expansion extrusion" were introduced to conventional ECAP and a novel process entitled equal channel angular expansion extrusion with spherical cavity(ECAEE-SC) was proposed.The plastic deformation behavior of commercially pure aluminum during ECAEE-SC process was investigated using finite element simulation and experimental validations.The results show that ECAEE-SC process is capable of combining some efficient severe plastic deformation(SPD) methods,the spherical die corner and expansion channel are the two main deformation zones.In ECAEE-SC process,the material is in an ideal compressive state.After a single pass of extrusion,the accumulated effective strain in the billet is about 3.5 with good deformation uniformity,demonstrating a considerable increase in the extrusion efficiency.Moreover,the extrusion experiment is consistent with the finite element simulation results.The extruded billet is free of macro crack with intact shape,and the microhardness increases from 36.6 HV to 70.2 HV.Therefore,the mechanical properties of the billet are greatly improved.