【摘要】 采用往复挤压(RE)工艺,在350℃挤压比为7.7∶1时,对工业纯铝L2进行了1道次和6道次往复挤压。结果发现,往复挤压可以改善材料的微观组织结构,显著细化晶粒,提高了组织的均匀性。然而往复挤压不能显著提高纯铝的硬度和拉伸强度。这是由于往复挤压过程中发生动态回复,极大地降低纯铝的位错密度,使材料软化,抵消了细晶强化作用。同时由于晶粒的细化和位错密度的降低,往复挤压提高了纯铝的延伸率。与室温等径转角挤压(ECAP)相比,350℃RE工艺可以提高工业纯铝L2的延展性,但对纯铝的细化效果不如ECAP。更多还原

【Abstract】 Pure Al L2 ingot was reciprocally extruded at 350℃ by 1 pass and 6 passes with the extrusion ratio being 7.7∶1.The results indicate that reciprocating extrasion(RE) can improve the microstructure,refine grain obviously. However,RE can not increase the hardness and tensile strength of pure Al significantly.Because dynamic recovery and low dislocation density counteract the strengthening effect of refined grain during RE,and thus RE is not able to increase the tensile strength.While the refined grains and low dislocation density contribute to the improvement of elongation.Compared with the Equal Channel Angular Processing(ECAP),RE operated at 350℃ can maintain the good ductility of pure Al.However,its effect of refinement is not as good as that of ECAP operated at room temperature.更多还原