摩擦攪拌処理された5083アルミニウム合金の高温変形中のミクロ組織とその後の室温機械的特性

Abstract

This work investigated the microstructural evolution occurring during high-temperature tensile tests (743 K, strain rate 1×10−3 s−1) of a friction stir processed polycrystalline solid solution 5083 aluminum alloy, along with the effect of the microstructure change on the room-temperature mechanical properties. Grain refinement was effectively achieved in the stir zone, with the mean observed grain size less than 10 µm. The nominal stress–nominal strain curve indicated that the flow stress drastically increased until a maximum stress value at which point fracture occurred. The value of elongation to failure exceeded 300%; this high ductility can be referred to as superplastic-like elongation. The area fraction of cavity increased with increasing strain. Room-temperature tensile tests at a strain rate of 1×10−3 s−1 revealed that the strength and ductility decreased with an increasing area fraction of cavity, and that the extent to which the strength and ductility are affected depends on the cavity.