| Tensile behavior of mechanically alloyed Al-8.5Fe-1.3V-1.7Si alloy extrusions, with various grain sizes ranging from 0.1 to 0.6 ㎛, were examined within the temperature range between 25℃ and 250℃. It was found that both tensile strength and ductility gradually decreased with increasing temperature and/or decreasing strain rate. The SEM fractographic examination showed that MA/PM Al-Fe-V-Si alloy extrusions failed by dimpled rupture, regardless of test conditions. The size and depth of dimples, however, differed considerably with different testing temperatures and strain rates. TEM micrographs of deformed specimens showed that the formation of dislocation structures within the grain was extremely limited at each test temperatures, and was further restricted at elevated temperatures. The present observations suggest that the enhanced dynamic recovery is responsible for the nil work hardening and plastic instabilities between growing voids at elevated temperatures, leading to a reduced tensile ductility. |
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