International Journal of Scientific and Research Publications, Volume 2, Issue 6, June 2012 1 ISSN 2250-3153 www.ijsrp.org Reviews on the Influences of Alloying elements on the Microstructure and Mechanical Properties of Aluminum Alloys and Aluminum Alloy Composites R. S. Rana, Rajesh Purohit, and S Das Department of Mechanical Engineering, Maulana Azad National Institute of Technology, Bhoapl-462051, India Abstract- In recent year’s aluminum and aluminum alloys are widely used in automotive industries. These are light weight (density of about 2.7g/cc),having good malleability and formability, high corrosion resistance and high electrical and thermal conductivity. High machinability and workability of aluminum alloys are prone to porosity due to gases dissolved during melting processes. However, in the engineering application pure aluminum and its alloys still have some problems such as relatively low strength, unstable mechanical properties. The microstructure can be modified and mechanical properties can be improved by alloying, cold working and heat treatment in this regards, this paper reports the influences of some alloying elements on the microstructures and mechanical properties of Aluminum alloys and aluminum alloy composites. Keywords- Aluminum alloy, aluminum alloy composites, Machinability, alloying, Heat treatment, Cold working I. INTRODUCTION luminium and aluminium alloy are gaining huge industrial significance because of their outstanding combination of mechanical, physical and tribological properties over the base alloys. These properties include high specific strength, high wear and seizure resistance, high stiffness, better high temperature strength, controlled thermal expansion coefficient and improved damping capacity.[1]. These properties obtained through addition of alloy elements, cold working and heat treatment. Alloying elements are selected based on their effects and suitability. The alloying elements may be classified as major and minor elements, microstructure modifiers or impurities, however the impurity elements in some alloys could be major elements in others[2]. In this paper the influences of alloying Such as Major elements (Si ,Cu ,Mg), Minor elements(Ni, Sn) ,Microstructure modifier elements(Ti, B, Sr ,Be ,Mn ,Cr) and Impurity elements(Fe, Zn) on microstructures and mechanical properties of aluminium alloys are reviewed. II. EFFECTS OF MAJOR ALLOYING ELEMENTS IN ALUMINIUM It's the foremost preliminary step for proceeding with any research work writing. While doing this go through a complete thought process of your Journal subject and research for it's viability by following means: The major alloying elements in Aluminum and aluminium alloys typically include Silicon (Si), copper (Cu) and magnesium (Mg). 2.1 Silicon(Si): Silicon is the most important single alloying element used in majority of aluminum casting alloys.[2] It is primarily responsible for so –called good castability (high fluidity,low shrinkage),low density(2.34g/cm3)which may be advantage in reducing total weight of cast component and has very low solubility in Aluminum therefore precipitates as virtually pure Si which is hard and improve the abrasion resistance. Si reduces thermal expansion coefficient of Al-Si alloys. Machinability is poor with addition of silicon in Aluminum. [3].Depending on the Si concentration in weight percentage, the Al-Si alloy systems are divided into three major categories: Hypoeutectic (<12 wt % Si), Eutectic (12-13 wt % Si), Hypereutectic (14-25 wt % Si). G.T. Abdel-Jaberet al [4] Investigate solidification and mechanical behaviour of Al-Si alloy against both the molding conditions and silicon content(3%-15%si).It was found that with increasing Si content, the solidification time increased as also a decrease liquidus temperature was observed upto 12% and then increased with Si% .ultimate tensile strength slightly increase with increase of silicon contents from 3% to 8%, whenever a liner increase in UTS was found with the increase of silicon content from 8% to 15% .It may related to change of eutectic composition and the creative of primary silicon at the hypereutectic. With increase of silicon content % elongation increase gradually and reach its maximum value at 12% Si .The minimum elongation% produced at 10mm mold thickness while 30mm mold thickness mold produce maximum elongation %. It may related to the effect of solidification rate.It was reported that hardness increase with increase the silicon content and reach maximum value70MPa at 12%Si content and then decrease down to 60 MPa related to 15% Si content. It may related to change of eutectic composition with the increase of silicon content and due to creative of primary silicon at the hypereutectic. It also reported that there is no pronounced effect of the mold thickness on the hardness and completely eutectic composition only has been perfectly modified and uniformly distributed. Wear rate and coefficient of friction of Al-Si casting alloys was also studied and it was observed that weight loss decreased down with increasing silicon contents up10% and then slightly increase. Higher weight loss was produced in case of 10mm mold thickness while lower weight loss in 30mm thickness mold .due cooling effect and present of hard Al2Si particles. A