This study presents the investigation on how heat treatment parameters, which are temperature, cooling method, and residence time, influence the microstructural and hardness properties of Ti6Al4V components produced on Ti6Al4V substrate using high speed selective laser melting technique. Heat treatment was performed on the produced samples before they were characterized for microstructure and hardness. The microstructure of the as-built sample contained large columnar β-grains that were filled with martensite α’ phase and had a high hardness of 383 ± 13 HV. At 1000 °C and residence time of maximum 4 h, better heat treatment parameters were seen for the selective laser melting (SLM) produced Ti6Al4V sample since an improved lamellar α + β microstructure was obtained at this condition. This microstructure is known to have improved tensile properties.

No abstract

This study investigated the microstructure evolution of the TiC/Ti-6Al-4V matrix composite produced using a 1073 nm continuous wave (CW), IPG Ytterbium fibre laser. The influence of thermal gradient, overlap, and re-melting of the previous layers on the microstructure of TiC/Ti6Al4V matrix composite samples was analyzed using the scanning electron microscope (SEM). The microstructure showed that the TiC/Ti-6Al-4V composite samples are composed of undissolved TiC, in-situ TiC (eutectic TiC and primary TiC), α Ti and β Ti. While martensite microstructure was observed on the Ti-6Al-4V alloy samples. It was observed that the single-track and single-layer composite samples are consists of blocky TiC, granular eutectic TiC, chain-shaped eutectic TiC and dendritic primary TiC phases. While the cube composite sample shows granular primary TiC and dendritic primary TiC. Dendritic primary TiC is observed in all composite samples.

Metal Matrix Composite (MMC) coatings of Tungsten Carbide (WC) and Nickel (Ni) powder were produced using laser cladding process. A crack free and good metallurgically bonded WC-Ni coating of about 5mm thick produced from varying both laser energy density and percent mixture of Ni and WC. In this study, the microstructure of WC-Ni coatings were characterised using optical microscope (OM), scanning electron microscope (SEM) with EDS, while mechanical properties of the coating were studied using Vickers hardness tester and abrasion wear resistance tester. It was found that the hardness and wear resistance increase as the percentage of WC increases.