Effects of Aging Temperature and Time on Microstructure and Mechanical Properties of LM 12 Aluminium Alloy

J. B. Agboola; R.H. Khan

J. B. Agboola Department of Materials and Metallurgical Engineering, Federal University of Technology, Minna, Nigeria
R.H. Khan Department of Materials and Metallurgical Engineering, Federal University of Technology, Minna, Nigeria

Keywords: LM12 Aluminium alloy, Aging temperature, Microstructure, Mechanical properties

Abstract

Mechanical properties of aluminum alloy are mainly dependent on their microstructure which is determined by
processing parameters. This study investigates the effects of aging temperature and time on the microstructure
and mechanical properties of LM12 aluminium alloy. Scrapped aluminium was melted in 100 Kg muffle furnace and cast into test bars. The as-cast specimens were solution treated in accordance with ASTM B917-01 at a temperature of 500 ºC for 2 hours and aged at 30 ºC-200 ºC for 2-10 hours. Microstructure and mechanical properties in terms of yield strength, hardness, and tensile strength were analyzed after solution heat treatment and aging. The results showed that the highest aging temperature and time was 170 ºC /8 hour at which Ultimate tensile strength, yield strength and hardness attained peak values of 405 MPa, 250 MPa and 125 HB respectively. The presence of fine coherent precipitates; CuAl2 accounted for the peak mechanical properties of the aged samples.

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