Effects of deformation temperature on the microstructure and mechanical properties of the AA3003 aluminium alloy

Abstract

The AA3003 aluminium alloy was deformed by isothermal compression in the deformation temperature range 300-500°C at a strain rate of 0.l s-1 with a Gleeble-1500 thermal simulator. The microstructure of the alloy was observed by OM and TEM, and the hardness was measured with a microhardness tester. The results show that the flow stress decreases with an increase of the deformation temperature. The dislocation density in the grain is large, and the polygonal structure occurs in the local area under low-temperature conditions. When the temperature reaches 400°C, the dislocation density decreases gradually, and the repetitive polygonal process occurs. The deformation mechanism is changed from dynamic recovery to dynamic recrystallization (DRX). The DRX volume fraction and grain size increase with an increase of the deformation temperature. The relationship between the micro-Vickers hardness and the DRX grain size of the alloy after hot deformation agrees with the Hall-Petch equation. At the strain rate of 0.1 s-1 , the optimum temperature of hot deformation for the alloy is about 400°C.

Study on the Modification Effect of Al-Sr Master Alloy on A356 Aluminum Alloy

“…When it is not modified, the eutectic silicon has a coarse needle and a sheet shape, and the alloy is easily cracked along the grain boundary or the plate-like silicon body, which makes the alloy brittle, resulting in a decrease in mechanical properties, particularly toughness of the alloy [4,5]. It has been found so far that potassium, sodium in alkaline metals, calcium and silver in alkaline earth metals, La, Ce, Nd, Eu in rare earth elements, Sb, Bi in nitrogen elements, and Te in oxygen elements all have a modification effect on the aluminum alloy [6,7]. Among them, Na has the best modification effect, and can obtain completely uniform fibrous eutectic silicon, followed by Sr and RE, while Te et al can only obtain lamellar eutectic silicon.…”