Microstructure Evolution and Mechanical Properties of Severely Plastically Deformed (SPD) Aluminum Alloys
Abstract
A combined experimental and modeling study has been carried out to characterize the structure and mechanical properties of severely plastically deformed (SPD) aluminum and its alloys as well as the effect of strengthening mechanism on fracture toughness and failure mode. This investigation is focused specifically on Equal Channel Angular Pressing (ECAP) and heavy cold rolling of high solute Al alloys. A particular reason for studying the high strength potentially achievable by these routes is the expectation that since the fracture toughness of precipitation hardened aluminum alloys is known to be degraded by grain boundary precipitates, the high strengths achievable by strain hardening without precipitation has a reasonable prospect of yielding a higher combination of yield strength and toughness than by conventional precipitation hardening. In this study it has been shown that SPD processing of high solute Al alloys can be carried out to higher strains before strain localization occurs if mechanical stress relieving is done prior to processing and that strengths unobtainable through precipitation hardening can readily be achieved by strain hardening. The effect of natural aging on strain hardening has been investigated and found to be a significant factor in the rate at which the flow stress increases with increasing plastic strain. It has been shown that strain hardened Al alloys are more ductile and exhibit higher strain hardening rates then precipitation hardened alloys at equivalent strengths and that strain hardening is a viable processing route for improving toughness. On the modeling side, we have developed new micromechanical finite element models that employ crystal plasticity constitutive framework and are able to successfully simulate texture evolution in the sample during complex routes of ECAP.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 31, 2007
- Accession Number
- ADA475483
Entities
People
- Brendon R. Donohue
- Christopher J. Hovanec
- Roger D. Doherty
- Ryan J. Vandermeulen
- Surya R. Kalidindi
Organizations
- Drexel University