The Effect in Strain Path on Mechanical Behaviour of an Al-Cu Alloy

Abstract

<p>The primary objective of the present study was to examine the effect of a 90° change in strain path, on the mechanical behaviour of an alloy, and its relation to the microstructure. In order to achieve this, the mechanical behaviour in uniaxial tension and compression of three different heat treatments of an Al 3.6 wt% Cu alloy and of pure aluminum were investigated. The heat treatments include a solid solution, a peak aged and an averaged condition. The results show a large 'Bauschinger' type effect in the overaged Al-Cu after 15% pre strain.</p> <p>The differences in mechanical behaviour in the materials studied were rationalized with the aid of transmission electron microscopy observations, and work hardening models from the literature. A simple model which relates the work hardening behaviour to a measurable microstructural feature via the initial obstacle spacing, is presented and compared with the experimental data.</p> <p>The fracture behaviour of each of the materials was also observed. The results are documented in a generalized form of a plane stress map, and discussed in terms of the movement of the material as yield surface in stress space as it work hardens. The potential use of this type of map for representing ductile fracture processes as well as intergranular surfaces ( for a wide range of stress states ) is discussed.</p>