Laser In Situ Synthesis and Computational Thermal Analysis of Ti-Al-xCr Alloys: Microhardness, Electrochemical Behavior and Tribological Properties

Abstract This work aims to evaluate the effect of chromium (Cr) as a dopant on microstructural evolution, microhardness, electrochemical behavior and tribological properties of ternary Ti-Al-xCr alloys synthesized via laser in situ alloying technology produced from their elemental powders. Computational thermal analyses of 3D printed Ti-48Al and Ti-Al-4Cr alloys were modeled and simulated by means of COMSOL Multiphysics. This was compared to the laser processing parameters to understand the thermal behavior of the alloys during manufacturing. The ternary Ti-Al-xCr alloys were synthesized at a scan speed of 10.58 mm/s and laser power of 450 W. The effects of Cr powder feed rate on Ti-Al matrix were studied at a gas carrier of 1 and 2 L/min, respectively. The microstructural evolution of Ti-Al-xCr alloys was examined using scanning electron microscopy equipped with energy-dispersive spectroscopy. The corrosion and oxidation behavior of the in situ alloyed Ti-Al-xCr were studied using potentiodynamic and thermal gravimetric techniques, respectively. Normalizing heat treatment on microhardness was performed at the temperature of 1350 °C. The findings showed that there was significant decrease in microhardness properties after HT. The computational model demonstrated minimal thermal distribution change proving that minimal or crack free alloys were developed. The results also showed that Cr addition to Ti-Al matrix resulted in improved tribological properties and oxidation behavior of the alloy.