Material characterization and corrosion behavior of hybrid coating Ti−Al−Si−Cu/Ti−6Al‐4V composite

Titanium alloy grade 5 is a grade of the titanium material that is in‐demand in the marine, aerospace, biomedical and turbo machinery industries. It offers great properties such as being light weight, good corrosion performance and great strength. However, some of the other properties, namely: its low hardness and poor tribological performance, has limited its various industrial application. Developments have focused on the enhancement of the surface properties without altering the bulk of the material. This has led to the laser metal deposition technique categorized under the additive manufacturing processes. It is a feasible technique that operates on layer‐by‐layer additive processing to manufactures whole parts or repair local damages in components. This study aims to ascertain the optimum processing conditions of the process by varying the laser intensity and scanning speed between 0.9 kW–1 kW and 1.0 m/min–1.2 m/min, respectively, while maintaining all the other process parameters. The specimens were produced by utilizing the ytterbium laser system to conduct laser surface alloying of Ti−Al−Si−Cu/Ti‐6Al‐4 V. Metallographic preparations, characterizations to conduct laser metal deposition (LMD), microhardness and corrosion test were conducted. It was deduced that Ti‐9Si‐3Cu alloy had the best optimum performance at 1 kW and 1.0 m/min. The hardness and corrosion were optimum improved at reduced scan speeds and increased laser power. The hardness distribution across the deposit, heat affected zone and substrate of the samples are also depicted. The diagrams show that across each sample, the hardness was improved on the produced clad but then the substrate superseded the hardness across the heat affected zone and base material of the laser metal deposition samples. However, the overall hardness across the zones for Ti−Al‐9Si‐3Cu was harder than Ti−Al‐11Si‐5Cu. Evidently, more grain structures were promoted at increased speed and appear finer since increasing the scan speed consequently increases the cooling rate because of less material interaction time.