The NiTi intermetallic possesses a number of good properties, such as high wear, oxidation, and corrosion resistance. This paper focuses on the deposition of NiTi intermetallic coatings on Ti6Al4V substrate by laser melting of Ti and Ni elemental powder mixtures. The effect of varying the Ti content in the NiTi composition on the microstructure and wear properties of the coatings was investigated. The microstructure of the NiTi intermetallic coatings were characterized by the scanning electron microscope (SEM) equipped with Energy Dispersive Spectroscope (EDS). The wear properties of the coatings were performed under accelerated dry sliding wear tests. The results obtained from the SEM/EDS analysis; show that the coatings consist of Ni and Ti elements from the feedstock, and the NiTi, NiTi₂and NiTi₃, intermetallic phases. Dry sliding wear analysis revealed that there is correlation between the hardness and the wear rate. The coatings displayed significant improvement in wear resistance up to 80% compared to the substrate.

This paper reports the effect of laser power density on the evolving properties of laser metal deposited titanium alloy. A total of sixteen experiments were performed, and the microstructure, microhardness and surface roughness of the samples were studied using the optical microscope (OP), microhardness indenter and stylus surface analyzer, respectively. The microstructure changed from finer martensitic alpha grain to coarser Widmastätten alpha grain structure as the laser power density was increased. The results show that the higher the laser power density employed, the smoother the obtained surface. The microhardness initially increased as the laser power density was increased and then decreased as the power density was further increased. The result obtained in this study is important for the selection of proper laser power density for the desired microstructure, microhardness and surface finish of part made from Ti6Al4V.

Direct energy deposition (DED) via laser processing, operated under standard conditions with a localised shielding gas, is a potential method for the manufacture of the γ-TiAl alloy. The freedom of operation, which includes the production of components via in situ melting of elemental powders, makes this method economically attractive. The goal of this study was to optimise the mass flow rates that lead to gamma phase formation during laser in situ melting of Ti and Al. A 3 kW Nd:YAG laser was used to melt Ti and Al elemental powders. Single clads were produced on Ti6Al4V substrates under localised argon shielding. The samples were heat-treated to promote microstructural homogenization and to provide thermal stress relief, after which they were characterized. Lamellar and duplex microstructures were obtained; depending on the Al feed rate and heat treatment temperatures. The Vickers microhardness was found to be predominantly dependent on Al content and the amount of twinning present. X-ray diffraction detected a proportional increase in the intensity of the γ phase peak with an increase in Al content, while α₂ peaks were dissolved and the twin γ-Ti₃Al₅ peaks diminished slightly. An alloy produced in this work achieved the target microstructure and properties associated with superior ductility and tensile strength in these materials, indicating that the technology has future potential in the production of Ti-Al materials for applications such as structural components or thermal barrier coatings.