The mechanical properties optimization of Al-6Si-0.5 Mg-2Cu-2Ni alloy by precipitation hardening

Abstract

The effect of artificial ageing on the hardness, microstructure, tensile strength, ductility and impact toughness of Al-6Si-0.5 Mg-2Cu-2Ni alloy was investigated. The alloy was homogenized for 24 h at 500 °C, solution treated for 2 h at 540 °C and aged for 1 h at various temperatures in the range 20–300 °C. The isochronal and isothermal ageing were monitored by hardness measurements. Tensile properties of the aged alloy were determined by tension tests at a constant strain rate of 10⁻³/s using an Instron tensile testing machine. The impact toughness reached its minimum at the peak hardness or peak strength. The microstructure and fracture surface were examined under a scanning electron microscope, and corelation between the mechanical properties and microstructures were investigated. The results show the optimum mechanical properties could be achieved by artificial ageing for 1 h at 225 °C.

Keywords:

• Precipitation hardening
• mechanical properties
• intermetallic phases
• SEM

Notes on contributors

Abul Hossain was born at Gazipur, Dhaka, in 1983. He received his BSc. and MSc. Engineering degrees in Materials and Metallurgical Engineering from the Bangladesh University of Engineering and Technology (BUET), Dhaka, in 2006 and 2009, respectively. He joined the Bashundhara Steel Complex Limited (BSCL) of Bashundhara Group, Bangladesh, in 2007 as a Production Engineer. Now, he has been serving as an Assistant Manager-Technical (Operation Engineer) in Sylhet Gas Fields Limited (A Company of Petrobangla, Energy and Mineral Resource Division, Government of Bangladesh) since 2009. He has obtained his PhD in Materials and Metallurgical Engineering at BUET in 2014. He has already published more than twelve technical papers in refereed International Journals and Conference Proceedings.

A.S.W. Kurny was born in February 1949, ASW Kurny obtained a Master’s degree in Metallurgical Engineering from Bangladesh University of Engineering and Technology (BUET) in 1973. He joined the Department of Metallurgical Engineering at BUET in 1974 as a Lecturer. He obtained a Ph. D. in Metallurgy from the Indian Institute of Science, Bangalore, in 1982. During his academic career at BUET, he has also served as Head of the Department, Provost of Students Residential Hall, Director of Students Welfare and Dean of Faculty of Engineering. Since 30 June 2014, he is on PRL.

Professor Kurny has supervised research work of 3 PhD and 18 Masters students of BUET Dhaka. He has authored several textbooks published by the BUET Text-Book Board. (adopted as textbooks at Engineering Institutions in Bangladesh). He has also published more than one hundred and fifty technical papers in refereed National and International Journals and Conference Proceedings.

Professor Kurny is Fellow and Member of several Professional bodies that include Institution of Engineers Bangladesh, Bangladesh Society of Mechanical Engineers, Bangladesh Crystallographic Association, Bangladesh Association for the Advancement of Science, Bangladesh Oceanographic and Maritime Institute and Bangladesh Society for Non-Destructive Testing. He served as Editor of the Journal of the Institution of Engineers, Bangladesh, during October 1991 to December 1994. He is presently a Member of the Editorial Board of several International Journals. He enjoys angling in still waters and kitchen gardening.

Disclosure statement

No potential conflict of interest was reported by the authors.