Tensile behaviour and damage characteristic of recycled aluminium alloys AA6061 undergoing finite strain deformation

Abstract

The effects of temperature and strain rate of hot-forged recycled aluminium alloys AA6061 are examined via uniaxial tensile test implementations in this paper. The tests are conducted at elevated temperatures of 100 °C, 200 °C and 300 °C, at two different strain rates of 10⁻⁴ s⁻¹ and 10⁻³ s⁻¹. The tensile behaviour and damage characteristic are analysed in terms of stress-strain curves and microstructural analysis, respectively. The microstructure and fracture surface of such materials are observed using Scanning Electron Microscope (SEM) and Optical Microscope (OM). The flow stress of recycled AA6061 increases with increasing strain rate and decreases with increasing temperature. ImageJ software is used to quantify void characteristics. It is observed that the quantity and size of the micro-voids are strain-rate sensitive. This is due to the growth and coalescence of the micro-voids. The OM analysis shows the gap between the grain boundaries becomes wider with the increasing temperature that affects the strength of the material. The outcome of this work gives valuable information before the appropriate applications, especially in automotive and aerospace fields, can be established. It can be agreed that there is still a need for improved recycling methods to fulfil the needs in the required applications, as shown by its primary resources. It is a massive challenge and an obvious drawback in such materials due to the degradation of material’s properties related to damage.