Effects of Cooling Rates on Thermal Profiles and Microstructure of Aluminium 7075

The effects of different cooling rates on thermal profiles and microstructures of aluminium 7075 are presented in this paper. The 7075 alloy was heated in a graphite crucible to 750 °C. In the experimental work two thermocouples were used to record the temperatures at the centre and 30 mm from the c...

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Main Authors:	Asnul Hadi, Ahmad, Naher, Sumsun, Brabazon, D.
Format:	Article
Language:	English English
Published:	Penerbit Universiti Malaysia Pahang 2014
Subjects:	TJ Mechanical engineering and machinery
Online Access:	http://umpir.ump.edu.my/id/eprint/4064/ http://umpir.ump.edu.my/id/eprint/4064/ http://umpir.ump.edu.my/id/eprint/4064/ http://umpir.ump.edu.my/id/eprint/4064/1/P133.pdf http://umpir.ump.edu.my/id/eprint/4064/2/fkm-2014-hasnul-effects_of_cooling_rates.pdf

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spelling	ump-40642018-05-16T03:56:02Z http://umpir.ump.edu.my/id/eprint/4064/ Effects of Cooling Rates on Thermal Profiles and Microstructure of Aluminium 7075 Asnul Hadi, Ahmad Naher, Sumsun Brabazon, D. TJ Mechanical engineering and machinery The effects of different cooling rates on thermal profiles and microstructures of aluminium 7075 are presented in this paper. The 7075 alloy was heated in a graphite crucible to 750 °C. In the experimental work two thermocouples were used to record the temperatures at the centre and 30 mm from the centre of the graphite crucible. A slow cooling rate condition was achieved by placing the crucible into a chamber with Kaowool insulation. A higher cooling rate was achieved by placing the crucible in open atmosphere with controlled air flow over the crucible. The slow and high cooling rates were 0.03 °C/s and 0.4 °C/s respectively. The Data Acquisition (DAQ) system implemented using LabVIEW software to record the temperature-time profiles. Using Differential Thermal Analysis (DTA), the enthalpy of phase change at each temperature was estimated from the cooling curves. The changes of cooling rate were directly related to phase transformation including at liquidus, eutectic and solidus temperatures. The dendritic coherency point (DCP) was determined from analysis of the temperature difference between two thermocouples. The formation of DCP was found to be delayed with use of the slow cooling rate. DCP occurred at 610.2 °C (0.75 fraction solid) for the slow cooling rate and at 633.1 °C (0.3 fraction solid) for the higher cooling rate. The microstructure features were also found to alter significantly with the different cooling rates used. The microstructure was more spheroidal for the higher cooling rate compared with the slow cooling rate. Penerbit Universiti Malaysia Pahang 2014 Article PeerReviewed application/pdf en http://umpir.ump.edu.my/id/eprint/4064/1/P133.pdf application/pdf en http://umpir.ump.edu.my/id/eprint/4064/2/fkm-2014-hasnul-effects_of_cooling_rates.pdf Asnul Hadi, Ahmad and Naher, Sumsun and Brabazon, D. (2014) Effects of Cooling Rates on Thermal Profiles and Microstructure of Aluminium 7075. International Journal of Automotive and Mechanical Engineering (IJAME), 9. pp. 1685-1694. ISSN 2180-1606 http://dx.doi.org/10.15282/ijame.9.2013.18.0140 DOI: 10.15282/ijame.9.2013.18.0140
repository_type	Digital Repository
institution_category	Local University
institution	Universiti Malaysia Pahang
building	UMP Institutional Repository
collection	Online Access
language	English English
topic	TJ Mechanical engineering and machinery
spellingShingle	TJ Mechanical engineering and machinery Asnul Hadi, Ahmad Naher, Sumsun Brabazon, D. Effects of Cooling Rates on Thermal Profiles and Microstructure of Aluminium 7075
description	The effects of different cooling rates on thermal profiles and microstructures of aluminium 7075 are presented in this paper. The 7075 alloy was heated in a graphite crucible to 750 °C. In the experimental work two thermocouples were used to record the temperatures at the centre and 30 mm from the centre of the graphite crucible. A slow cooling rate condition was achieved by placing the crucible into a chamber with Kaowool insulation. A higher cooling rate was achieved by placing the crucible in open atmosphere with controlled air flow over the crucible. The slow and high cooling rates were 0.03 °C/s and 0.4 °C/s respectively. The Data Acquisition (DAQ) system implemented using LabVIEW software to record the temperature-time profiles. Using Differential Thermal Analysis (DTA), the enthalpy of phase change at each temperature was estimated from the cooling curves. The changes of cooling rate were directly related to phase transformation including at liquidus, eutectic and solidus temperatures. The dendritic coherency point (DCP) was determined from analysis of the temperature difference between two thermocouples. The formation of DCP was found to be delayed with use of the slow cooling rate. DCP occurred at 610.2 °C (0.75 fraction solid) for the slow cooling rate and at 633.1 °C (0.3 fraction solid) for the higher cooling rate. The microstructure features were also found to alter significantly with the different cooling rates used. The microstructure was more spheroidal for the higher cooling rate compared with the slow cooling rate.
format	Article
author	Asnul Hadi, Ahmad Naher, Sumsun Brabazon, D.
author_facet	Asnul Hadi, Ahmad Naher, Sumsun Brabazon, D.
author_sort	Asnul Hadi, Ahmad
title	Effects of Cooling Rates on Thermal Profiles and Microstructure of Aluminium 7075
title_short	Effects of Cooling Rates on Thermal Profiles and Microstructure of Aluminium 7075
title_full	Effects of Cooling Rates on Thermal Profiles and Microstructure of Aluminium 7075
title_fullStr	Effects of Cooling Rates on Thermal Profiles and Microstructure of Aluminium 7075
title_full_unstemmed	Effects of Cooling Rates on Thermal Profiles and Microstructure of Aluminium 7075
title_sort	effects of cooling rates on thermal profiles and microstructure of aluminium 7075
publisher	Penerbit Universiti Malaysia Pahang
publishDate	2014
url	http://umpir.ump.edu.my/id/eprint/4064/ http://umpir.ump.edu.my/id/eprint/4064/ http://umpir.ump.edu.my/id/eprint/4064/ http://umpir.ump.edu.my/id/eprint/4064/1/P133.pdf http://umpir.ump.edu.my/id/eprint/4064/2/fkm-2014-hasnul-effects_of_cooling_rates.pdf
first_indexed	2023-09-18T21:58:34Z
last_indexed	2023-09-18T21:58:34Z
_version_	1777414244742987776

Effects of Cooling Rates on Thermal Profiles and Microstructure of Aluminium 7075

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