DOI : 10.55981/metalurgi.2023.714 © 2023 Author(s). This is an open access article under the CC BY-SA license (http://creativecommons.org/licenses/by-sa/4.0) Metalurgi is Sinta 2 Journal (https://sinta.kemdikbud.go.id/journals/profile/3708) accredited by Ministry of Education, Culture, Research, and Technology, Republic Indonesia Metalurgi (2023) 3: 83 - 94 ejurnalmaterialmetalurgi.lipi.go.id THE EFFECT OF AlTi5B1 AND ALTAB Ti80 WITH A COMBINATION OF AlSr15 AND Mg ADDITIONS ON STRENGTH AND DUCTILITY OF A356 ALUMINUM ALLOYS Afghany Mostavan a, *, Asep Ridwan b , Arif Basuki b , Husaini Ardy b a Doctoral Program of Materials Science and Engineering a,b Department of Materials Science and Engineering, Faculty of Mechanical and Aerospace Engineering Institut Teknologi Bandung Jl. Ganesha 10, Bandung, Indonesia 40132 *E-mail: 33720001@mahasiswa.itb.ac.id Received: 20-05-2023, Revised: 16-11-2023, Accepted: 20-11-2023 Abstract The current study aims to analyze microstructural changes affecting the A356 aluminum alloy, a hypoeutectic Al-Si- Mg alloy. This aluminum alloy is well-known for its strength, resistance to corrosion, lightweight, and heat treatability. The main objective of this research is to improve the strength and ductility of A356 alloys by using a synergistic strategy that includes AlTi5B1 and ALTAB Ti80 for microstructural alteration in combination with AlSr15 and Mg. The experimental results show that including all constituents in the as-cast condition enhances the ultimate tensile strength and elongation. Furthermore, in the heat-treated state, the addition of ALTAB Ti80 effectively maintains tensile strength (σuts=233.7 MPa), yield strength (σy=180.3 MPa), and elongation (e=5.8%). Additionally, when combined with Mg, the tensile strength and yield strength exhibit further improvement (σuts=253 MPa and σy=215.7 MPa); however, elongation is significantly reduced (e=2.7%). Keywords: A356 alloy, microstructure modification, mechanical properties 1. INTRODUCTION The A356 aluminum alloy, which is classified in the hypoeutectic group of the Al-Si phase diagram, is widely used in a variety of industrial sectors. Referred to as type AC4CH (JIS) and AlSi7Mg (ISO/DIN), A356 exhibits favorable characteristics during metal mold filling, possessing excellent mechanical properties, high resistance to dynamic loads, and exceptional corrosion resistance [1]. Hence, it is commonly used to fabricate pump housings, impellers, blowers, aircraft components, and vehicle parts [2]-[3]. The A356 aluminum alloy is widely used in the automobile sector, particularly in the production of cast wheel vehicles using GDC (gravity die casting) and LPDC (low-pressure die casting) techniques [4]. The quality of these casting wheel vehicles is influenced by factors such as alloy composition, casting process techniques, cooling rate, and heat treatment [5]. Specifications for casting wheels necessitate specific requirements, including a minimum ultimate tensile strength (σuts) of 277 MPa, minimum yield strength (σy) of 200 MPa, minimum elongation (e) of 7-12%, and a hardness range of 80-95 HB [4]-[6]. The ASTM B108 standard specifies the minimum ultimate tensile strength (σ uts) of 260 MPa, the minimum yield strength (σy) of 150 MPa, and the minimum elongation (e) of 3% for aluminum alloy A356 after it completed the T6 heat treatment[8]. However, it is worth noting that A356 alloy exhibits high strength but low ductility, necessitating simultaneous enhancement of both properties. The mechanical characteristics of aluminum alloys, particularly A356, are primarily determined by microstructure, morphology, grain