The Effect of Time, Percent of Copper and Nickel on the Natural Precipitation Hardness of Al – Cu – Ni Powder Metallurgy Alloys Using Design of Experiments

Mohammad M. Hamasha, Ahmad T. Mayyas, Mohammed T. Hayajneh, Adel M. Hassan

Department of Automotive Engineering, Clemson University-International Center for Automotive Research (CU-ICAR), 4 Research Drive, Greenville, SC 29607, USA.
Department of Systems Science and Industrial Engineering, State University of New York at Binghamton, Binghamton, NY 13850, USA.
Industrial Engineering Department, Jordan University of Science and Technology, P.O. Box 3030, Irbid 22110 Jordan.

DOI: 10.4236/jmmce.2011.106036                

Abstract

In this investigation, the effect of time, percentage of copper and nickel on the hardness property of aluminum based powder metallurgy alloys were studied. A full factorial analysis with four levels for each factor was used. The samples were produced using powder metallurgy process, and then subjected to natural aging where heat treatment was conducted for all samples together at 550°C for 3 hours before quenching in water. Then, the samples were left at room temperature for 936 hours (39 days) to allow traces atoms to diffuse and form coherent phases which increase the hardness. It was found that the hardness was firstly increased with time for about 300 hours after the quenching time, and then it tends to remain constant after that. However, the hardness drop at overage stage was not observed until the end of 936 hours. To get a full analysis of the natural aging we used design of experiment tool to study the effect of %Cu, %Ni and aging time on the hardness. The results showed that the hardness was influenced significantly by all considered factors and interactions between them.

Keywords

Al; Powder Metallurgy; solution treatment; Natural Precipitation hardening.

Conflicts of Interest

The authors declare no conflicts of interest.

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