Thermomechanical treatment of 2014 aluminium alloy

Abstract

The effect of thermomechanical treatment on the flow stress, fracture strain, structure, and precipitation behaviour of commercial grade 2014 aluminium alloy has been investigated. Specimens in the supersaturated and aged conditions were plastically deformed in torsion tests in the temperature range 293–493 k and strain rate range 2·8 ×10−3−2·5 s−1. It is stated that the starting condition of the alloy acts dominantly on the flow stress, fracture strain, and thermally activated processes, which take place during aging. An increase in temperature results mainly in a reduction of flow stress in the aged alloy and an increase in flow stress in the supersaturated alloy. The supersaturated alloy exhibits negative strain rate sensitivity over the entire range of applied temperature while for the aged alloy it is exhibited only in the temperature range 293–393 K. The effect of temperature and strain rate on the fracture strain of the supersaturated alloy is negligible, but the fracture strain of the aged alloy increases with temperature and decreases with strain rate. In the supersaturated alloy, the process of strain aging is dominant during deformation at room temperature and at higher temperatures precipitation aging and recovery are dominant. In the aged alloy, strain aging is dominant in the temperature range 293–443 K and recovery is dominant only at the highest test temperature (493 K).MST/616