Electrical resistance-based fatigue assessment and capability prediction of extrudates from recycled field-assisted sintered EN AW-6082 aluminium chips
“…Furthermore, the proposed multiscale formulation is expected to contribute to the development process of advanced non-destructive electrical resistance-based testing methods used to analyse defect structures in specimens, e.g. [23].…”
Motivated by the influence of deformation-induced microcracks on the effective electrical properties at the macroscale, an electro-mechanically coupled computational multiscale formulation for electrical conductors is proposed. The formulation accounts for finite deformation processes and is a direct extension of the fundamental theoretical developments presented by Kaiser and Menzel (Arch Appl Mech 91:1509–1526, 2021) who assume a geometrically linearised setting. More specifically speaking, averaging theorems for the electric field quantities are proposed and boundary conditions that a priori fulfil the extended Hill–Mandel condition of the electro-mechanically coupled problem are discussed. A study of representative boundary value problems in two- and three-dimensional settings eventually shows the applicability of the proposed formulation and reveals the severe influence of microscale deformation processes on the effective electrical properties at the macroscale.
“…Furthermore, the proposed multiscale formulation is expected to contribute to the development process of advanced non-destructive electrical resistance-based testing methods used to analyse defect structures in specimens, e.g. [23].…”
Motivated by the influence of deformation-induced microcracks on the effective electrical properties at the macroscale, an electro-mechanically coupled computational multiscale formulation for electrical conductors is proposed. The formulation accounts for finite deformation processes and is a direct extension of the fundamental theoretical developments presented by Kaiser and Menzel (Arch Appl Mech 91:1509–1526, 2021) who assume a geometrically linearised setting. More specifically speaking, averaging theorems for the electric field quantities are proposed and boundary conditions that a priori fulfil the extended Hill–Mandel condition of the electro-mechanically coupled problem are discussed. A study of representative boundary value problems in two- and three-dimensional settings eventually shows the applicability of the proposed formulation and reveals the severe influence of microscale deformation processes on the effective electrical properties at the macroscale.
“…Koch et al investigated the same alloy EN AW-6082 processed at different process parameters of 400°C and 40 MPa by field-assisted sintering technology (FAST). The sintered specimens were cold extruded and heattreated (T6) to surpass the mechanical properties of the heat-treated reference [22]. A comparable pulsed electric current sintering (PECS) process was investigated on a smaller scale by Cislo et al, using a Gleeble 3800 and a sintering temperature of about 450°C with a pressure of 64 MPa.…”
Abstract. In order to promote aluminum scrap recycling and reduce remelting losses, solid-state recycling processes are subject to increasing academic attention. These processes range from severe plastic deformation (SPD) to diffusion-based processes like field-assisted sintering (FAST). In this study, a FAST-based recycling route consisting of precompaction, FAST, and impact extrusion of dry machined EN AW-6082 and EN AW-7075 aluminum chips was used to create multi-material parts from different aluminum alloys. To examine the effect on the resulting part quality, two different hybrid material layouts were created during cold compaction of the chips. The subsequent sintering process took place in a field-assisted sintering (FAST) machine at 400°C and 500°C for a duration of 5 min under a pressure of 85 MPa, allowing for the analysis of inter-chip diffusion. These sintered blanks were then cold-formed by impact extrusion. Metallographic and computed tomography analyses as well as hardness measurements were performed for property evaluation before and after heat-treatment.
“…In recent years, there has been a lot of research work on the recycling of aluminum alloy chips using modern and innovative techniques without the liquid phase [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 ].…”
Section: Introductionmentioning
confidence: 99%
“…Koch A. et al [ 19 ] used aluminum chips pre-pressed, sintered field-assisted sintering technology (FAST), and then extruded without the solid phase, which allowed for obtaining higher fatigue properties than in conventional recycling methods. An innovative method was presented by M. E. Mehtedi [ 20 ], in which he combined co-extrusion with friction mixing, ensuring a high-quality outer surface, while inside there were various sizes of porosity.…”
Recycling of raw materials and is crucial for the production of new products for the global economy. The aim here is, on the one hand, to reduce energy consumption, and, on the other hand, to obtain materials with similar functional properties. The study undertook research on the possibility of processing AlSi11 aluminum chips by compaction and co-extruding to obtain a product in the form of a flat bar with mechanical properties not lower than those of the cast materials. The performed tests and the developed technique allowed to obtain flat bars with more favorable mechanical properties (Yield Strength YS ≥ 155 MPa; Ultimate Tensile Strength UTS ≥ 212 MPa) than the castings (YS ≥ 70 MPa ≥ 150 MPa). The weldability evaluation tests revealed that the material is susceptible to porosity. The presence of pores, which reduces the cross-section (up to 60%), reduces the tensile strength (up to 20 MPa). The typical joint structure and plasticity is obtained, which indicate the possibility of tensile strength improvement.
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