Publication

Abstract : Titanium Aluminide (TiAl) alloys are promising materials for applications in aerospace, automotive and power plant sectors because of their low density and high oxidation resistance. Conventionally these alloys are processed using Casting and Powder Metallurgy techniques. However, processing of these alloys is a major challenge due to their low ductility and fracture toughness. Therefore, research is ongoing to find new processing methods for TiAl alloys. Additive Manufacturing is one of the processing techniques that is currently being explored to fabricate these alloys. In this work, Laser Engineered Net Shaping (LENSTM) technique is used to remelt a TiAl alloy sample fabricated using Electron Beam Melting (EBM) under different processing conditions. The focus of this work is to understand the thermal behavior during laser processing of TiAl alloys using a combination of computational and experimental approaches. Transient thermal finite element analysis is carried to simulate the laser remelting process. The dimensions of the melt pool, and the maximum temperature within the melt pool are extracted from the FEM models. Next, melt pool depths of the remelted samples have been measured using Scanning Electron Microscopy. The value of the laser absorption coefficient of TiAl alloy is then determined by comparing the measured and FEM predicted melt pool depths.