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Hot press as a sustainable direct recycling technique of aluminium: mechanical properties and surface integrity

Meltless recycling technique has been utilized to overcome the lack of primary resources, focusing on reducing the usage of energy and materials. Hot press was proposed as a novel direct recycling technique which results in astoundingly low energy usage in contrast with conventional recycling. The a...

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Main Authors: Yusuf, Nur Kamilah, Lajis, Mohd Amri, Ahmad, Azlan
Format: Article
Language:English
Published: MDPI 2017
Subjects:
TJ Mechanical engineering and machinery
TS200-770 Metal manufactures. Metalworking
Online Access:http://eprints.uthm.edu.my/5127/1/AJ%202017%20%28278%29%20Hot%20press%20as%20a%20sustainable%20direct%20recycling.pdf
http://eprints.uthm.edu.my/5127/
http://dx.doi.org/10.3390/ma10080902
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spelling my.uthm.eprints.51272022-01-06T02:11:33Z http://eprints.uthm.edu.my/5127/ Hot press as a sustainable direct recycling technique of aluminium: mechanical properties and surface integrity Yusuf, Nur Kamilah Lajis, Mohd Amri Ahmad, Azlan TJ Mechanical engineering and machinery TS200-770 Metal manufactures. Metalworking Meltless recycling technique has been utilized to overcome the lack of primary resources, focusing on reducing the usage of energy and materials. Hot press was proposed as a novel direct recycling technique which results in astoundingly low energy usage in contrast with conventional recycling. The aim of this study is to prove the technical feasibility of this approach by characterizing the recycled samples. For this purpose, AA6061 aluminium chips were recycled by utilizing hot press process under various operating temperature (Ts = 430, 480, and 530 °C) and holding times (ts = 60, 90, and 120 min). The maximum mechanical properties of recycled chip are Ultimate tensile strength (UTS) = 266.78 MPa, Elongation to failure (ETF) = 16.129%, while, for surface integrity of the chips, the calculated microhardness is 81.744 HV, exhibited at Ts = 530 °C and ts = 120 min. It is comparable to theoretical AA6061 T4-temper where maximum UTS and microhardness is increased up to 9.27% and 20.48%, respectively. As the desired mechanical properties of forgings can only be obtained by means of a final heat treatment, T5-temper, aging after forging process was employed. Heat treated recycled billet AA6061 (T5-temper) are considered comparable with as-received AA6061 T6, where the value of microhardness (98.649 HV) at 175 °C and 120 min of aging condition was revealed to be greater than 3.18%. Although it is quite early to put a base mainly on the observations in experimental settings, the potential for significant improvement offered by the direct recycling methods for production aluminium scrap can be clearly demonstrated. This overtures perspectives for industrial development of solid state recycling processes as environmentally benign alternatives of current melting based practices. MDPI 2017 Article PeerReviewed text en http://eprints.uthm.edu.my/5127/1/AJ%202017%20%28278%29%20Hot%20press%20as%20a%20sustainable%20direct%20recycling.pdf Yusuf, Nur Kamilah and Lajis, Mohd Amri and Ahmad, Azlan (2017) Hot press as a sustainable direct recycling technique of aluminium: mechanical properties and surface integrity. Materials, 10 (902). pp. 1-18. ISSN 1996-1944 http://dx.doi.org/10.3390/ma10080902
institution Universiti Tun Hussein Onn Malaysia
building UTHM Library
collection Institutional Repository
continent Asia
country Malaysia
content_provider Universiti Tun Hussein Onn Malaysia
content_source UTHM Institutional Repository
url_provider http://eprints.uthm.edu.my/
language English
topic TJ Mechanical engineering and machinery
TS200-770 Metal manufactures. Metalworking
spellingShingle TJ Mechanical engineering and machinery
TS200-770 Metal manufactures. Metalworking
Yusuf, Nur Kamilah
Lajis, Mohd Amri
Ahmad, Azlan
Hot press as a sustainable direct recycling technique of aluminium: mechanical properties and surface integrity
description Meltless recycling technique has been utilized to overcome the lack of primary resources, focusing on reducing the usage of energy and materials. Hot press was proposed as a novel direct recycling technique which results in astoundingly low energy usage in contrast with conventional recycling. The aim of this study is to prove the technical feasibility of this approach by characterizing the recycled samples. For this purpose, AA6061 aluminium chips were recycled by utilizing hot press process under various operating temperature (Ts = 430, 480, and 530 °C) and holding times (ts = 60, 90, and 120 min). The maximum mechanical properties of recycled chip are Ultimate tensile strength (UTS) = 266.78 MPa, Elongation to failure (ETF) = 16.129%, while, for surface integrity of the chips, the calculated microhardness is 81.744 HV, exhibited at Ts = 530 °C and ts = 120 min. It is comparable to theoretical AA6061 T4-temper where maximum UTS and microhardness is increased up to 9.27% and 20.48%, respectively. As the desired mechanical properties of forgings can only be obtained by means of a final heat treatment, T5-temper, aging after forging process was employed. Heat treated recycled billet AA6061 (T5-temper) are considered comparable with as-received AA6061 T6, where the value of microhardness (98.649 HV) at 175 °C and 120 min of aging condition was revealed to be greater than 3.18%. Although it is quite early to put a base mainly on the observations in experimental settings, the potential for significant improvement offered by the direct recycling methods for production aluminium scrap can be clearly demonstrated. This overtures perspectives for industrial development of solid state recycling processes as environmentally benign alternatives of current melting based practices.
format Article
author Yusuf, Nur Kamilah
Lajis, Mohd Amri
Ahmad, Azlan
author_facet Yusuf, Nur Kamilah
Lajis, Mohd Amri
Ahmad, Azlan
author_sort Yusuf, Nur Kamilah
title Hot press as a sustainable direct recycling technique of aluminium: mechanical properties and surface integrity
title_short Hot press as a sustainable direct recycling technique of aluminium: mechanical properties and surface integrity
title_full Hot press as a sustainable direct recycling technique of aluminium: mechanical properties and surface integrity
title_fullStr Hot press as a sustainable direct recycling technique of aluminium: mechanical properties and surface integrity
title_full_unstemmed Hot press as a sustainable direct recycling technique of aluminium: mechanical properties and surface integrity
title_sort hot press as a sustainable direct recycling technique of aluminium: mechanical properties and surface integrity
publisher MDPI
publishDate 2017
url http://eprints.uthm.edu.my/5127/1/AJ%202017%20%28278%29%20Hot%20press%20as%20a%20sustainable%20direct%20recycling.pdf
http://eprints.uthm.edu.my/5127/
http://dx.doi.org/10.3390/ma10080902
_version_ 1738581340836593664
score 13.211869

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