Abstract
Titanium and Titanium –based alloys have been used for aerospace materials for many years. Recently, those alloys are now being increasingly utilised for automotive, industrial, chemical, energy industries and consumer applications because of its excellent tensile and fatigue strength, corrosion resistance and high toughness- to- mass ratio, temperature strength and Young modulus’s values. However, despite these numerous applications, their general usages are often restricted because of limitations in mechanical properties and poor anti-friction properties exhibited in selected service conditions. There are different rapid solidification methods that have been put forward by some authors to address these deficiencies. Laser Metal Deposition has the potential to offer all specific solutions to key engineering problems over the traditional metal-working techniques. However, the purpose of this research work focuses on the laser metal deposition of CpTi /TiC composites coatings on Ti6A14V as a substrate by the laser melting of CpTi and TiC elemental powder mixtures. The process parameters involved with the LMD method include the laser power, traverse speed, powder-flow rate, and gas-flow rates. The characterization was done using OM, SEM, EDS, microhardness and tensile testing. The laser power was varied between 800W to 1600 W, while all the other parameters were kept constant. The results show that as laser power increases, the average hardness and the strength values also increase continuously. The results revealed that the microhardness values increases from 383 HV0.1 for the substrate and they reach a peak as high as 460 HV0.1 for sample A3 and the lowest value of 364 HV0.1 for sample A2. The tensile test showed that the average UTS for the four samples were 1545.18 MPa while the YTS and the percentage elongation were 932.60 MPa and 67% respectively. The average grain size of the substrate materials was determined to being 44.4 μm. The highest average grain size for sample A4 and lowest is for sample A1 of the deposited samples were found to be 79.8 μm and 67.7 μm respectively.
M.Ing. (Mechanical Engineering)