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Induction heating-assisted single point incremental sheet forming was established for Ti-6Al-4V thin sheets at closed and above beta-transus temperature (980 °C). In order to eliminate geometric inaccuracy and adherence of lubricant on the surface caused by elevated temperature, a cooling lubricant system was designed for the forming tool to decrease the thermal expansion and friction. A radial basis function (RBF)-based tool path optimisation was developed to study the measured geometric accuracy, temperature, and forming force. By adjusting cooling lubricant control and integrating the RBF framework, the first optimised tool path was used to collect the results and to validate with the finite element (FE) model and theoretical geometric profiles. The output data were further studied by RBF and generate a second optimised tool path. The measured geometric coordinates revealed that the error percentage has been reduced to less than 5%. Further, the microstructure evolution analysed by scanning electron microscopy (SEM) indicated noticeable oxidation and alpha-layer for temperature around 1040 °C and the phenomenon was removed at temperature closed to 950 °C. The surface roughness and energy-dispersive X-ray analysis (EDX) revealed the optimised tool path distributed significant improvement in surface quality. The cooling lubricant system indicated optimal performance with RBF optimised tool path to support constant temperature and reduce friction and lubricant adherence on the surface.

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Pulsation of current is widely employed in Tungsten Inert Gas (TIG) welding of titanium alloys. In the current study, the influence of welding speed and welding currents (peak and background) on the properties pulsed TIG welded Ti-5Al-2.5Sn alloy were investigated. The weldment characteristics which were analyzed included weld zone size, microstructure, residual stresses, tensile and impact properties. Increasing the welding speed and gradient of pulsed current enhanced grain strengthening in the fusion zone (FZ) which was attributed to increased cooling rate. Such a welding condition was also favorable in achieving full penetration weldments with a reduced; heat affected zone width, grain size in FZ and residual stresses. However, a tensile strength superior to the base metal was observed. The impact toughness reduced by increasing the pulsed current gradient and a high value of both peak and background currents were required to improve the impact toughness of the weldments.

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