| Equal Channel Angular Pressing(ECAP) was carried out on the 6061 aluminum alloy at room temperature, 373K, 423K, and 473K. The microstructures and mechanical properties of specimens pressed at different temperatures and cycles were investigated. All specimens pressed at different temperatures show ultra fine-grained microstructures with the average grain size less than 0.5 ㎛ and dislocation cell structure. When the pressing temperature increased higher than 423K, the tensile strength of the specimens decreased and the total elongation increased. In case of specimens pressed for 4 cycles at 473K, the fraction of grains having high angle grain boundaries is higher than that pressed at room temperature. The specimen pressed for 4 cycles at room temperature shows higher increase of the 0.2% yield strength, ultimate tensile strength and hardness, and much higher decrease of work hardening index. |
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