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对不同路径和不同道次下铝粉烧结材料的等通道转角挤压工艺进行了试验研究,用光学显微镜、扫描电子显微镜和透射电镜分析了粉末烧结材料在不同工艺条件下的晶粒细化规律和致密行为,并测量了挤压后试样的密度和硬度等性能.结果表明,等通道转角挤压工艺对粉末烧结材料具有很强的致密效果和细化效果,可显著提高其力学性能.在单道次变形中,大剪切塑性变形和高静水压力状态是粉末烧结材料获得良好的致密效果的关键;在多道次变形中,变形量的累积和不同的剪切特征不断地改变内部的孔隙形状,使内部基体材料进一步致密.而晶粒的细化效果则取决于变形中的静水压力、变形量和剪切特征等关键因素.
The equal-channel corner extrusion process of aluminum powder sintered materials under different paths and different passes was studied. The grain refinement rules of powder sintered materials under different technological conditions were analyzed by optical microscope, scanning electron microscope and transmission electron microscope And density behavior of the samples were measured.The density and hardness of the sample after extrusion were measured.The results show that the equal channel corner extrusion process has strong compactness and refining effect on the powder sintered materials and can significantly improve its mechanical properties. In single pass deformation, large shear plastic deformation and high hydrostatic pressure conditions are the key to good compactness of powder sintered materials. In multi-pass deformation, the cumulative amount of deformation and different shear characteristics continuously change the internal Of the pore shape, so that the internal matrix material is further compact, while the grain refinement depends on the deformation hydrostatic pressure, deformation and shear characteristics and other key factors.