Method to decode stress-strain diagrams to identify the structure-strength relationships in aged aluminum alloys

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Vol. 709; pp. 9 - 16
• Main Authors: Saimoto, S., Singh, M.A., Langille, M.R., Levesque, J., Inal, K., Niewczas, M., Woll, A.R.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 02.01.2018; Elsevier BV
• Subjects: Aluminum alloys; Aluminum base alloys; Constitutive relations; Constitutive relationships; Deformation; Deformation mechanisms; Dislocation interactions; Dispersed particle; Elongation; Extrusion; Failure; Forensic engineering; Industrial development; Materials processing; Metal industry; Nano-void formation; Nano-void growth; Plastic flow; Properties (attributes); Quality control; Small angle X ray scattering; Strengthening; Stress-strain curves; Stress-strain diagram; Stress-strain relationships; Tensile tests; Thermomechanical treatment; Dislocation interactions; Nano-void growth; Strengthening; Constitutive relations; Stress-strain diagram; Nano-void formation; Dispersed particle
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2017.10.004

Leading-edge infrastructure renovation is driven by innovations in materials processing to optimize desired properties. The immediate challenge for the metal industry is the development of effective and efficient materials quality-control practices. At present, mechanical and sheet forming properties are assessed using standard tensile tests to measure yield and ultimate tensile strengths, as well as the total elongation to failure. The resulting stress-strain data is used as a “pass-fail” test to ensure that the product meets industry specifications. We report a new method of constitutive relation analyses (CRA) that can extract fundamental information regarding the underlying crystalline mechanisms of deformation and failure from standard stress-strain data. The CRA method is applied to industrial extrusion product made from AA6063 aluminum alloy to demonstrate how this type of forensic examination can be used to direct changes to thermo-mechanical processing to optimize desired material properties. The CRA prediction of point-defect generation and nano-void formation leading to ductile failure during plastic flow was validated by small angle X-ray scattering (SAXS) studies.