Microstructure and Stress Mapping in 3D at Industrially Relevant Degrees of Plastic Deformation

TL;DR

This study provides detailed 3D X-ray imaging data of aluminum under high plastic deformation, revealing intra-grain stress variations and their implications for damage and material properties.

Contribution

It offers the first comprehensive 3D experimental stress mapping at industrially relevant deformation levels, aiding the development of predictive models.

Findings

Intra-grain stress variations reach 36 MPa.

Inter-grain stress variations reach 76 MPa.

Stress concentrations may initiate damage.

Abstract

Strength, ductility, and failure properties of metals are tailored by plastic deformation routes. Predicting these properties requires modeling of the structural dynamics and stress evolution taking place on several length scales. Progress has been hampered by a lack of representative 3D experimental data at industrially relevant degrees of deformation. We present an X-ray imaging based 3D mapping of an aluminum polycrystal deformed to the ultimate tensile strength (32% elongation). The extensive dataset reveals significant intra-grain stress variations (36 MPa) up to at least half of the inter-grain variations (76 MPa), which are dominated by grain orientation effects. Local intra-grain stress concentrations are candidates for damage nucleation. Such data are important for models of structure-property relations and damage.