1Department of Mechanical Engineering,
Osun State College of Technology,
P. M. B. 1011, Esa – Oke, Nigeria.
2Department of Mechanical Engineering,
Ladoke Akintola University of Technology,
Ogbomoso, Oyo,State, Nigeria
*(Address of correspondence)
ABSTRACT: This study focused on the effect of heat treatment on the microstructure of Aluminum - Zinc Alloy. The composition of the Aluminum alloy used is eighty percent (80%) of Aluminum and twenty percent (20%) of Zinc. The method of casting employed is Sand casting, while annealing and quenching were heat treatment processes it’s subjected to. The microstructure is taken. It is concluded that heat treatment have effect on the microstructure of Aluminum - Zinc alloy and responded well to Oil quench.
[Keywords: Aluminum-Zinc Alloy, Heat treatment, Microstructure, Tensile test, Hardness test, Annealing and Water quenching.]
The extensive application of metals in the field of Engineering has necessitated the need for metal heat treatments in order to meet the taste of firm, industries and individual as a result of their wide engineering application. One of the major engineering fields where the application of various metals was used is Automobile engineering. In order to reduce motor vehicle weight, many automotive components have been redesigned to take advantage of material such as lightweight and polymers. To this end aluminum casting alloys are being widely used for many automotive components (CAD, 2006), the alloys have good casting characteristics, reasonable mechanical properties, and are heat treatable (Melo, Rizzo and Santos, 2005). Material science and engineering today has developed to a stage where correlations between microstructure, properties and application can be established for many commonly used alloys. The structure of a material is related to its composition, properties, processing history and performance (Argo and Gruziesk,(1988) and Rooy,(1993)). And therefore, studying the microstructure of aluminum alloys provides information linking its composition and processing to its properties and performance interpretation of microstructure requires the understanding of the process by which various structures are formed. There are many processes by which aluminum alloys can be formed. The major process that is common and the focus of this study is the Sand casting process (Albert, (1957)). One of the common defects in aluminum castings is porosity (Monroe, (2005) and Tyler, 1981)). It is a clear fact that the quantity and the appearance of the porosity are very crucial to the mechanical properties of the aluminum alloy casting, most especially the fatigue properties because the pore in micro scale are primary source of initial cracks for the final failure of the aluminum parts. Due to this the aluminum alloys structure need to be improved by metal treatment to have the required properties. Olanrewaju (2000), stated that metal treatments are classified into two groups namely-: Heat treatment and surface treatment. Surface treatment as corrosion resistance operations includes phosphating chroming nickeling, anodization and so on, While heat treatment as structural adjuster includes hardening, tempering toughening and so on (Ojediran and Alamu, (2004) and Vincet,(1968)). In this study, the effects of such heat treatment are determined to know the extent of their impact on the aluminum – Zinc alloys (Al- Zn). MATERIAL AND EXPERIMENTAL TECHNIQUES
The targeted materials composition, uses and forms are as follows: TABLE 1 THE COMPOSITION, USES AND FORMS OF ALUMINUM ALLOYS |Composition | Uses | Forms...