Executive Summary : | Additive Manufacturing (AM) techniques that involve creation of products by incremental layer by layer deposition of material has enjoyed unprecedented growth due to its ability to generate new geometries with ease. Present metal AM techniques can be broadly classified into two classes. One class of AM techniques use metal powders as starting material, and the second class of AM techniques rely on the use of metal wire as the starting material and use various energy sources to melt and deposit the metal wire in a layer wise manner. Recently, an AM technique based on the use of semisolid metal as a starting printing material was explored. This technique relies on controlling the rheological behaviour of semi-solid alloy slurries in a way such that it retains shape upon printing. It is known that the solid and liquid fraction in an alloy can be tailored to exhibit viscoelastic behaviour so that the alloy can be extruded through a nozzle and thereby depositing layers of metal in the semisolid state. Previous studies on semi-solid alloy processing have revealed that temperature and external shearing are two important factors that can be manipulated to effectively tailor the microstructure, the rheological characteristics, and the formability of semisolid alloys. The viscosity of the alloy can be tailored such that after being extruded and deposited in a layer wise manner, it forms the shape laid out by the movement of the nozzle. Currently, there is no technology or working prototype available in the market or in literature to 3D print a semisolid metal feedstock akin to Fused Deposition Modelling (FDM) technique that is widely used for polymers. Aluminium alloys make up the next important structural alloys after steel by volume. A review of the literature shows that there is no direct work being carried out on the semisolid metal based Additive Manufacturing techniques. There exists immense scope to work in this AM technique in aluminium alloys. There is ample scope for both fundamental work and the knowledge can be applied to make products. Therefore, the present proposal will attempt a systematic study of process parameters involved in manufacturing semisolid-based AM based aluminium alloy components. In order to achieve the objectives the project has been divided into three important tasks as follows: Task 1 # Development of printhead for semisolid-based additive manufacturing (SAM) Task 2 # Studies on selected aluminium alloys printed using SAM technique Task 3 # Establish microstructure-property correlation in SAM printed alloys |