Microstructure Investigations of Streak Formation in 6063 Aluminum Extrusions by Optical Metallographic Techniques

Voort, George Vander; Suárez-Peña, Beatriz; Lozano, José Antonio Flórez

doi:10.1017/s143192761300010x

Cited by 15 publications

(5 citation statements)

References 29 publications

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“…The Mg2Si and FeAlSi could be identified from the black and white colors, respectively. This finding was similar to the study by Voort et al, [20]. The AR sample consists of coarse Mg 2 Si and FeAlSi while the NT and TT500 consist of mixed coarse and fine Mg 2 Si and FeAlSi.…”

Section: Resultssupporting

confidence: 92%

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: Resultssupporting

confidence: 92%

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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“…Overall, all the extrudates exhibited the presence of Mg2Si and spheroidal Al-Fe-Si rich precipitates, which could be identified from the black spot and light grey, respectively. This result was similar to the finding in the study by Voort et al [27]. The extrudate of solid as-received consist of coarse Mg2Si and AlFeSi precipitate, while the chip-based extrudates of untreated and thermally-treated showed fine precipitate.…”

Section: Resultssupporting

confidence: 91%

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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“…Gjonnes et al [22] attributed the formation of shingles on rolled Al alloys due to local adhesion and sticking, followed by deformation and rupture of the metal surface after passing through the deformation rolls. Vander voort et al [30] showed that the difference in local number density of second phases or intermetallics on the Al surface causes local differences in temperature rise, and extent of deformation under rolling and thus leads to a heterogeneity in surface roughness causing streaks on the rolled Al surface. In general the defects on rolled Al alloys are reported to be formed mainly due to the presence of intermetallic phase particles that interact with the roll counter face and modify the local microstructure, texture and morphology of the Al metal under high shear forces [31].…”

Section: Accepted Manuscriptmentioning

confidence: 99%

Characterization of blisters on powder coated aluminium AA5006 architectural profiles

Zaffaroni

Gudla

Din

et al. 2019

Engineering Failure Analysis

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Investigation of premature blistering and delamination of coated AA5006 window frames using scanning (SEM) and transmission electron microscopy (TEM), glow discharge optical emission spectroscopy and X-ray photoelectron spectroscopy (XPS) is presented. SEM of the blisters revealed corrosion of Aluminium and accumulation of corrosion products at the interface of coating and metal. TEM and XPS analysis revealed a thin and non-homogenous hexavalent Cr conversion layer. High number density of intermetallics, and surface defects from metal forming process resulted in a defective conversion coating leading to reduced corrosion protection of aluminium in the presence of water and Cl from atmosphere.

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Microstructure Investigations of Streak Formation in 6063 Aluminum Extrusions by Optical Metallographic Techniques

Cited by 15 publications

References 29 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

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

Characterization of blisters on powder coated aluminium AA5006 architectural profiles

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