Microstructural Study of Ti-6Al-4V Produced with TiH ₂ Powder

In the aerospace industry, 80-90% of the titanium used in airframes has been from Ti-6Al-4V. This alloy is used throughout the section of an aircraft - fuselage, nacelles, landing gear, wing and empennage. In gas turbine engines Ti-6Al-4V is used in static and rotating components. Castings are used for the manufacture of more complex static components; forgings are typically used for moving parts. Conventional methods for obtaining titanium alloys require special conditions of controlled atmosphere that culminates in a high production cost. In this paper it was investigated the peculiarities of the typical microstructure of Ti-6Al-4V produced by powder metallurgy using TiH₂ powder. Samples were produced from the initial mixture of Al, V and TiH₂ powders, followed by cold uniaxial and isostatic pressing with subsequent densification by sintering in temperatures between 800-1400°C, in vacuum. Sintered samples were characterized by means of x-ray diffraction, Vickers micro hardness, scanning electron microscopy and density analysis. Due to the complete dissolution of the alloying elements in the titanium matrix and the presence of hydrogen during the sintering stage, an improved combination of homogenous microstructure, densification and mechanical properties could be achieved.