Evaluation of hardness strength and microstructures of recycled Al chip and powder AA6061 fabricated by cold compaction method.

Kadir, Muhammad Irfan Ab; Mustapa, Mohammad Sukri; Mahdi, Ahmed Sahib; Kuddus, Suriyanti; Samsi, Mohd Arif

doi:10.1088/1757-899x/165/1/012012

Cited by 9 publications

(4 citation statements)

References 3 publications

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“…Recycling aluminium via solid-state technique can be performed using various types of severe deformation processes. To this date, the deformation process such as forging [7][8][9], rolling [10,11] and extrusion [12][13][14] have been applied in previous research works. It has been claimed in a majority of research studies that the method is feasible in transforming recycled chips into semi-finished products.…”

Section: Introductionmentioning

confidence: 99%

Effect of Thermally Formed Alumina on Density of AlMgSi Alloys Extrudate Recycled Via Solid State Technique

Wagiman

Mustapa

Lajis

et al. 2021

ARFMTS

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Solid state recycling of aluminium via hot extrusion is a sustainable technique. The process performed before hot extrusion plays a vital role on the extrudate properties. In this study, the effect of naturally and thermally formed in-situ alumina on the extrudate density were investigated. Fours type of material identified as a solid as-received, non-treated recycle chip, 300 0C thermally treated recycle chip and 500 0C thermally treated recycle chip were prepared for the experiment. Prior to extrusion, the recycle chips were compacted into a chip-based billet, preheated and immediately extruded into a semi-finished product. The density test performed on the chip-based extrudate found that the type of chips influenced the density. The chip-based extrudate made of 300 0C and 500 0C thermally treated chips resulted in higher density than solid as-received and non-treated chips. Chip-based extrudate produced from 500 0C thermally treated chips resulted in density of 2724 kg/m3, which is the highest among the specimen. This density value was 0.7 % higher compared to the solid as-received extrudate. Microstructure examination on the cross-section revealed the alumina entrapped in the chip-based extrudate. The alumina entrapped in 500 0C thermally treated chips specimen was more prone than the non-treated and 300 0C thermally-treated chips. This finding explains the variation in the extrudate density.

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Section: Introductionmentioning

confidence: 99%

Effect of Thermally Formed Alumina on Density of AlMgSi Alloys Extrudate Recycled Via Solid State Technique

Wagiman

Mustapa

Lajis

et al. 2021

ARFMTS

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show abstract

“…Most of the research reports claim that the aluminium chips were successfully transformed into various semi-finished product via direct recycling technique. The technique can be performed through various severe plastic deformation process such as forging [1], [5], [8]- [10], rolling [11]- [13] and extrusion [14]- [16].…”

Section: Introductionmentioning

confidence: 99%

Direct Recycling of Aluminium Chips into Composite Reinforced with <i>In Situ</i> Alumina Enrichment

Wagiman

Mustapa

Lajis

et al. 2020

MSF

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Direct hot extrusion is a sustainable technique for recycling aluminium chips into aluminium matrix composite. Reinforcement particles are used to improve the mechanical properties. In this paper, the reinforcing medium of alumina layer that forms on the chip surface were enriched in situ via thermal treatment. Three types of chips were prepared namely; non-treated, treatment of 300 °C for 60 minutes and treatment of 500 °C for 10 minutes. The chips were compacted into chip-based feedstock having a density of 75 %, 85 % and 95 %. The chip-based feedstocks were preheated at 500 °C for 3 hours before extrude. Tensile test performed on the extrudate found that variation in the types of chip and feedstock relative density has affected the ultimate tensile strength. The highest ultimate tensile strength of 256 MPa is obtained from the condition of chip treated at 300 °C for 60 minutes and a feedstock density of 85 %. Elemental analysis on the extrudates reveals that the oxygen content is increased when the extrudates made from heat treated chip. Apart from heat treatment, the oxygen content also affected by the feedstock density.

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“…The solid-state technique uses severe plastic deformation to bond the chips together. Many types of deformation processes, including forging [4,8,[11][12][13], rolling [14][15][16], and hot extrusion [17][18][19] were investigated in previous studies, which highlighted that the processes were feasible for the conversion the conversion of the recycled chips into a semi-finished product. Furthermore, the mechanical properties of products were also comparable to those products produced by conventional remelting techniques [20].…”

Section: Introductionmentioning

confidence: 99%

“…The alumina layer also could be thermally enriched in-situ through the thermal treatment on the chips before compaction. On top of that, the treatment also softens the chips, enabling cold compaction, the process before extrusion, to be performed at a significantly lower pressure compared to untreated chips [13]. The enrichment of alumina expected to give the same effect as the addition of alumina powder due to the possibility of the hot extrusion to disperse the layer into the fine particles.…”

Section: Introductionmentioning

confidence: 99%

Effect of Thermally-Treated Chips on Density of AlMgSi Alloys Recycled Using Solid-State Technique

et al. 2020

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Solid-state recycling is a sustainable technique for recycling aluminium scrap, and the process before recycling is essential to control the physical properties of the product. In this work, the effect of the thermally-treated chips on the extrudate density was investigated. The aluminium chips were thermally-treated to enrich the alumina layer and reduce compaction pressure during chips compaction before recycled using direct hot extrusion. The chips that were transformed into compacted billets were extruded directly without melting and conducted according to 24 full factorial experimental design. The density test on the recycle extrudate found that the density variation ranged from 2724 to 2983 kg/m3. The ANOVA result showed that all factors investigated were statistically significant. The most significant factor was the preheating temperature, followed by extrusion ratio, chip treatment temperature, chip treatment time, and the interaction of chip treatment-time–extrusion ratio. The predictive model suggested by the ANOVA is useful to predict the density with 1% error. Microstructure examination revealed the presence of alumina entrapped in the recycle extrudate, in which thermal-treated chips contained more alumina than that of the untreated chips. The result indicated that the thermal treatment performed on the chips had enriched the in-situ alumina, affecting the density of the recycle extrudate.

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Evaluation of hardness strength and microstructures of recycled Al chip and powder AA6061 fabricated by cold compaction method.

Cited by 9 publications

References 3 publications

Effect of Thermally Formed Alumina on Density of AlMgSi Alloys Extrudate Recycled Via Solid State Technique

Effect of Thermally Formed Alumina on Density of AlMgSi Alloys Extrudate Recycled Via Solid State Technique

Direct Recycling of Aluminium Chips into Composite Reinforced with <i>In Situ</i> Alumina Enrichment

Effect of Thermally-Treated Chips on Density of AlMgSi Alloys Recycled Using Solid-State Technique

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