Reprocessing of AW2007, AW6082 and AW7075 aluminium chips by using sintering and forging operations

Behrens, Bernd‐Arno; Frischkorn, Conrad; Bonhage, Martin

doi:10.1007/s11740-014-0542-2

Cited by 18 publications

(6 citation statements)

References 14 publications

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“…Table 2. Measured densities after pre-compaction (ρ c ) and sintering (ρ), with calculated relative densities based on reports, suggesting a final density of 2.71 kg/cm 3 [33] and 2.832 kg/cm 3 [24] for chip-based specimens.…”

Section: Density Measurementsmentioning

confidence: 80%

“…Therefore, relative densities were determined according to two individual absolute densities, to show both upper and lower end of estimations regarding final specimen densities achieved. While Behrens et al [33] used 2.71 g/cm 3 for their calculations on Al EN AW 6082 chips, Paraskevas et al [24] reported of fully dense samples of the same alloy reaching 2.832 g/cm 3 , indicating a much higher amount of oxides. Evaluation of specimens described in this work, based on measurements of the individual samples and calculated relative densities for both above stated cases, is presented in Table 2.…”

Section: Density Measurementsmentioning

confidence: 99%

See 1 more Smart Citation

Solid State Recycling of Aluminum Alloy Chips via Pulsed Electric Current Sintering

Cislo

Kronthaler

Buchmayr

et al. 2020

JMMP

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Based on high energy demand of the primary production and losses during secondary production, alternative recycling of aluminum becomes a popular research topic. Compared to both primary and secondary production of aluminum, solid state recycling offers energy savings and reduced material losses during processing by surpassing an inefficient melting step. In this work, a direct recycling route for machining chips via pulsed electric current sintering (PECS) is evaluated. Therefore, necessary processing steps for a complete recycling route are briefly outlined. After cleansing, EN AW 6082 chips, provided by Neuman Aluminium GmbH, Marktl, Austria, are compacted with variable loads and consolidated via PECS on two separate systems to enable a comparison. Produced specimens are examined with density measurements, optical microscopy and the bonding quality is evaluated by Vickers micro-hardness measurements. In combination with elevated temperature and deformation, applied current promotes consolidation amongst chips and improvements in density, hardness and microstructure are achieved. The results of this work clearly show a positive effect of PECS on the bonding amongst chips, but further research will be necessary to separate and understand influences of single processing parameters. Additionally, all processing steps from collection to consolidation have to be taken into account to achieve industrial implementation.

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Section: Density Measurementsmentioning

confidence: 80%

Section: Density Measurementsmentioning

confidence: 99%

Solid State Recycling of Aluminum Alloy Chips via Pulsed Electric Current Sintering

Cislo

Kronthaler

Buchmayr

et al. 2020

JMMP

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“…Selected aluminum alloy for SSR process was EN AW 6082 extruded bar in T6 temper condition due to the wide application of this alloy in the machining processes. Furthermore, authors noticed there were only a few papers that mentioned the possibility of the solid state recycling for this specific alloy [19,28,29]. Chemical composition of the selected aluminum alloy was provided according to the EN-573-3 standard in Table 2.…”

Section: Machining Chips Fabrication and Cold Compactionmentioning

confidence: 99%

Statistical Analysis of the Combined ECAP and Heat Treatment for Recycling Aluminum Chips Without Remelting

Krolo

Lela

Dumanić

et al. 2019

Metals

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The main aim of this paper is to present an environmentally friendly method for aluminum recycling. Development of new recycling technologies in order to increase scrap reuse potential and CO 2 emission savings are of the main importance for aluminum circular economy. In this paper, aluminum chips waste was recycled without any remelting phase in order to increase energy and material savings. The presented process is usually called solid state recycling or direct recycling. Solid state recycling process consists of chips cleaning, cold pre-compaction and hot direct extrusion followed by a combination of equal channel angular pressing (ECAP) and heat treatment. Influence of holding time during solid solution treatment and both artificial aging time and temperature on mechanical properties of the recycled EN AW 6082 aluminum chips were investigated. A comprehensive number of the experiments were performed utilizing design of experiments approach and response surface methodology. Regression models were developed for describe the influence of heat treatment parameters for presented solid state recycling process on mechanical properties of the recycled samples. Utilizing novel procedure high quality recycled samples were obtained with mechanical properties comparable with commercially produced EN AW 6082 aluminum alloy in T6 temper condition. Metallographic analysis of the recycled samples was also performed.In order to reduce the negative effect on the environment, various authors recognized solid state recycling (SSR) as a possible alternative to the conventional aluminum recycling process [4][5][6][7][8][9]. When SSR is employed, material losses are much smaller because the remelting phase is completely avoided. Aluminum is a highly reactive material and it has a tendency to form aluminum oxide on its surface. This is even more pronounced for lightweight aluminum scrap due to its high surface to mass ratio. During the remelting process this oxide is floating on the melt surface mixed with dross. Therefore, aluminum lightweight scrap (chips, foils, and sheet skeletons) is problematic when conventional recycling technology is used because up to 20% of the aluminum can be lost due to the mixing with dross and burning [9]. According to previous research papers concerned with SSR process, it is possible for material yield to be over 90% when this type of recycling is employed, while energy consumption can be only 10% compared to conventional recycling process that uses remelting [6][7][8]. Furthermore, manufacturing profiles from solid state bonded chips gives a 96% saving in CO 2 emission compared to production from billets made by conventional recycling of aluminum manufacturing waste [8]. In order to produce SSR samples with appropriate quality, the combination of the high temperature, normal stress, shear stress, and plastic deformation should be achieved [6,7]. Therefore, the most used process for SSR is direct hot extrusion, but lately severe plastic deformation (SPD) processes opened new possibilities [10]. SPD i...

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“…However, additional research of the quality of the SSR samples was done in this paper where tensile tests were performed, as well as microstructure and micro porosity analysis with scanning electron microscope. According to the available literature SSR of mentioned aluminium alloy was recycled only in two more papers, however with different SSR processes than presented here [21], [22].…”

Section: Introductionmentioning

confidence: 99%

Enhanced Mechanical Properties of Aluminium Alloy EN AW 6082 Recycled without Remelting

Krolo¹,

Lela²,

Ljumović³

et al. 2019

Teh. vjesn.

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Main aim of this research was to investigate unconventional method for aluminium recycling. Recycling process presented in this research was performed in solid state and therefore is called solid state recycling (SSR) or direct recycling. Main aim of direct recycling approach is to reduce greenhouse gasses emission compared with primary aluminium production and conventional recycling. Other advantages are higher scrap material yield during recycling and energy savings. In this paper, SSR process consisted of aluminium chips hot extrusion and afterwards severe plastic deformation process at room and elevated temperatures. Mechanical properties of the solid state recycled samples obtained by presented process were comparable with samples obtained by conventional manufacturing. Furthermore, it was shown that additional plastic deformation after hot extrusion significantly improved mechanical properties of the recycled samples compared with those recycled only by hot extrusion. Analysis of both microstructure and density analysis was also performed.

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Reprocessing of AW2007, AW6082 and AW7075 aluminium chips by using sintering and forging operations

Cited by 18 publications

References 14 publications

Solid State Recycling of Aluminum Alloy Chips via Pulsed Electric Current Sintering

Solid State Recycling of Aluminum Alloy Chips via Pulsed Electric Current Sintering

Statistical Analysis of the Combined ECAP and Heat Treatment for Recycling Aluminum Chips Without Remelting

Enhanced Mechanical Properties of Aluminium Alloy EN AW 6082 Recycled without Remelting

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