In this paper we report a quantitative study, using small-angle X-ray scattering, of the precipitation kinetics during ramp heating and isothermal ageing in an AA7075 aluminium alloy processed by high-pressure torsion. The precipitation behaviour has been compared with that of the same material processed in a conventional manner and observations are supplemented by transmission electron microscopy for precipitate and grain size characterization using automated crystal orientation mapping. After severe plastic deformation and natural ageing, the material is shown to contain a high density of GP zones. During ageing, the precipitate size distribution becomes bimodal, with small precipitates behaving similarly to those of the conventionally processed material and large ones associated with the crystalline defects and reaching large sizes at considerably lower temperatures and shorter times as compared to the conventionally processed material.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Ceramics and Composites
- Polymers and Plastics
- Metals and Alloys