铝粉烧结材料等通道转角挤压组织性能演变及机理分析

Equal channel angular extrusion (ECAE) is a new method to obtain ultra-fine grain materials．Experiments of ECAE are conducted for pure aluminum powder sintered material under different routes and passes．The grain refinement regulation and densification behavior of powder material during ECAE are deeply investigated under different conditions with optical telescope，scan electronic telescope and transmission electronic telescope．The density and hardness of the extruded samples are measured．The experiment results show，ECAE has powerful densification and refinement effects and the mechanical properties of powder materials are improved．In single ECAE，large shear plastic deformation and high hydrostatic stress state are the key factors to obtain high density material．At the same time，in multiple passes ECAE，the inner pore shape is changed and the powder material is compacted further by the accumulated deformation and different shear deformation characters．The grain refinement effect depends on some key factors such as hydrostatic stress，strain and shear deformation character etc.．These studies provide essential theoretical foundation for manufacturing the same material with SPD.