International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056 Volume: 07 Issue: 06 | June 2020 www.irjet.net p-ISSN: 2395-0072 © 2020, IRJET | Impact Factor value: 7.529 | ISO 9001:2008 Certified Journal | Page 2356 IMPACT OF STRONTIUM, MAGNESIUM AND NICKEL ON MECHANICAL PROPERTIES OF Al-5 Si-3 Cu (A319) ALUMINIUM ALLOY Venkitesh P.S 1 , Sreejith P.S 2 1 Workshop Instructor, Sreerama Govt. Polytechnic College, Thriprayar, Thrissur 2 Professor, Dean, Faculty of Engineering CUSAT, Kerala, India ---------------------------------------------------------------------***--------------------------------------------------------------------- Abstract - Aluminium and its alloys have number of applications, mainly, in the field of aerospace and automobile industry. A319 (Al-Si) based alloys are used in cylinder heads, engine blocks, suspension etc. The major drawback for this alloy is that of low tensile strength (180 - 220MPa). Porosity also is a major problem in high pressure and gravity die casting process used for the manufacturing of components. In the present work the major aim is to study the effects of alloying elements Strontium, Magnesium and Nickel in the mechanical properties ofA319. Development of porous free castings using Stir casting technique is also an objective of this work. Six castings were developed for this study (A319, A319 – 0.04Sr, A319 - 0.05 Ni, A319 –0.5Mg - 0.04Sr and A319 – 0.5Mg – 0.5Ni – 0.04Sr). The microstructure and EDAX analysis were done to identify the phases present. Different mechanical tests were carried out to study the effect of these alloying elements on basic A319 alloy. The results showed that these alloying elements have a positive influence on A319 alloy. It is seen that the tensile strength of the material has improved for each alloy composition and maximum tensile strength is obtained as238 MPa for A319 – 0.5Mg –0.5Ni – 0.04Sr alloy. Key Words: Aluminium, A319 (Al-Si) based alloys, Stir Casting, EDAX. 1. INTRODUCTION Aluminium is an element in the boron group with symbol Al and atomic number 13. It is a silvery- white, soft, nonmagnetic, ductile metal. Aluminium is remarkable for the metal’s low density and for its ability to resist corrosion due to the phenomenon of passivation. Structural components made from aluminium and its alloys are vital to the aerospace industry and are important in other areas of transportation and structural materials [6]. This work is based on aluminium silicon alloys. The aluminium silicon alloys have wide range of applications in the automobile industry. A319 (Al- 5Si- 3Cu) is the mostly used aluminium silicon alloy. Castings manufactured from this alloy can be heat treated to improve the mechanical properties. The machining properties are better than the high silicon aluminium alloys and considerably improve with heat treatment [5]. Engine blocks, engine cover and suspension parts are manufactured using A319 alloy. When these parts need to be heavy loaded conditions, the weight of the component should be increased to have higher strength which leads to reduced mileage of automobiles. High pressure die casting, which is used for manufacturing A319 components, is found to have porosity [6]. The objective of this project is to develop a new alloy based on A319 aluminium alloy system without porosity having high tensile strength by optimizing alloying compositions with different additives which are explained in the literature survey. Now days, the need for materials having high strength to weight ratio is increasing. It is seen that the A319 alloy which is used in suspensions systems has only a low tensile strength (only having a peak tensile strength of 220MPa). This lack of strength is a major problem and the industry has been looking at improved materials with higher tensile strength. Many research studies are going on around the world to create newer materials with improved properties. Three possible solutions for increasing the tensile strength of A319 without compromising on other properties are, 1. Development of a new alloy 2. Addition of Nano or micro particles to improve strength 3. Alloying A319 with different elements and optimizing the percentage addition for obtaining maximum tensile strength for the alloy In this thesis, the effect of alloying elements Strontium, Magnesium and Nickel on A319 alloy are studied. Stir casting techniques is used to study the effect of these alloying elements. 1.1 A319 ALLOY A319 (Al- Si- Cu) aluminum alloy is widely used for a range of engineering applications where moderate stress is envisaged. Its casting characteristics make it ideal for castings of varying section thickness as it can cope with heavy and moderately thin sections. Castings manufactured from this alloy can be heat treated to improve the mechanical properties. The machining properties are better than the high silicon aluminum alloys and considerably improve with heat treatment. They are used in automotive cylinder heads, internal combustion engine crankcases, suspensions, engine mountings, gearboxes, etc;