Grain refinement and high strain rate superplasticity in alumunium 2024 alloy processed by high-pressure torsion

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Vol. 622; pp. 139 - 145
• Main Authors: Alhamidi, Ali, Horita, Zenji
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.01.2015
• Subjects: Aluminum base alloys; Al–Cu Alloy; Grain boundary sliding; Grain refinement; High strain rate; High strain rate superplasticity (HSRS); High-pressure torsion (HPT); Plastic deformation; Severe plastic deformation (SPD); Superplastic forming; Superplasticity; Torsion; Ultrafine-grained (UFG) materials; High-pressure torsion (HPT); High strain rate superplasticity (HSRS); Severe plastic deformation (SPD); Ultrafine-grained (UFG) materials; Al–Cu Alloy
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2014.11.009

An Al-2024 alloy was processed by high-pressure torsion (HPT) to produce an ultrafine-grained structure with a grain size of ~240nm. A maximum elongation of ~750% was attained with an initial strain rate of 1×10−2s−1 at 673K, demonstrating the advent of high strain rate superplasticity through grain refinement by the HPT processing. Evaluation of the strain-rate sensitivity and the activation energy for the deformation confirmed that grain boundary sliding through grain boundary diffusion is the rate-controlling process for the superplastic deformation of the HPT-processed Al-2024 alloy.