In-plane anisotropy and tensile deformation behaviour of aluminium alloy AA 2014 forge plates

Abstract

Plastic flow behaviour and fracture mechanism of aluminium alloy AA 2014 forged plates under tensile loading conditions are investigated and the results obtained are presented and discussed in the present study. The effects of heat treatment (namely, solution treatment and artificial ageing) on micro-structural homogeneity, tensile behaviour and nature of fracture were studied using hardness, tensile, optical and scanning electron microscopy methods. Experimental engineering stress–engineering strain and true stress–true strain data of the aluminium alloy AA 2014 in different ageing conditions have been analysed using Hollomon, Ludwik and Ludwigson plastic flow relationships. The alloy is found to exhibit moderate degree of in-plane anisotropy and anisotropic index. Further, the alloy in both solution-treated and aged conditions exhibits three different stages of strain-hardening rate and the highest strain-hardening rate occurs at regions of lower strain both in solution-treated and peak-aged conditions. It is also observed that the longitudinal specimen (L parallel to forging direction) exhibits higher strain hardening, while the specimen with T orientation exhibits lowest strain-hardening rates both in solution-treated and aged conditions. The alloy under study in all the heat treatment conditions exhibits ductile fracture mechanism with higher density of uniformly distributed macro- and micro-dimples.