Electrical resistance-based fatigue assessment and capability prediction of extrudates from recycled field-assisted sintered EN AW-6082 aluminium chips

• Published in: Materials characterization Vol. 169; p. 110644
• Main Authors: Koch, Alexander, Bonhage, Martin, Teschke, Mirko, Luecker, Lukas, Behrens, Bernd-Arno, Walther, Frank
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.11.2020
• Subjects: Computed tomography; Fatigue behaviour; Lifetime prediction; Resistance measurements; Solid-state-recycling; Fatigue behaviour; Lifetime prediction; Solid-state-recycling; Resistance measurements; Computed tomography
• ISSN: 1044-5803; 1873-4189
• DOI: 10.1016/j.matchar.2020.110644

The possibility to directly extrude semi-finished products using a solid-state-recycling process is a promising alternative to the remelting process, which is highly energy-intensive. Therefore, aluminium chips, normally considered as scrap, are used as the basis for the recycling. The recycling process consists of a cold compaction process, a field-assisted sintering (FAST) process to consolidate the chips, and finally a forward rod extrusion process. Compared to approaches which break the oxide layers by applying high shear stresses and deformations, necessary for an adequate welding of the chips, quasistatic and cyclic properties and capabilities are significantly increased. The defect structure of specimens, which was determined by means of computed tomography and which significantly influences the lifetime, could be correlated well with pre-test electrical resistance measurements. Finally, these findings were used to establish a lifetime calculation model based on unique electrical resistance measurements prior to mechanical testing. •Field-assisted sintering is a well-suited process to recycle chips.•The quasistatic properties of chip-based specimens exceed the reference.•Fatigue properties in this study exceed conventional recycling approches.•The defect volume determined by CT fits well to electrical resistance measurements.•A lifetime calculation model based on the resistance shows excellent results.