Search Results

Turbine blades for airplanes work in adverse conditions, under corrosive environment and high temperatures and pressure conditions. Ti-6Al-2Sn-4Zr-2Mo alloy was developed for high temperatures applications in aerospace area. In this work, Ti-6Al-2Sn-4Zr-2Mo alloy was obtained by powder metallurgy using titanium hydride powders. Samples were manufactured by blended elemental method from a sequence of uniaxial and cold isostatic pressing with subsequent densification by sintering among 800 up to 1400°C, in vacuum. The objective of this work is the analysis of microstructural evolution from the powders dissolution with the increase of the sintering temperature. The alloy was characterized by scanning electron microscopy, X-ray diffraction and Vickers microhardness measurement. Density was measured by Archimedes method.

The powder metallurgy allows titanium alloy production with savings of energy and time with higher microstructural homogeneity than those obtained by conventional processes. The processing of titanium alloys is increasing in industry, since these alloys presenting superior mechanical properties than commercially pure titanium. Ti-Zr alloys with zirconium contents ranging from 10 to 40 wt% have been investigated by melting process along the last years. In these alloys were reported characteristics as excellent corrosion resistance and high biocompatibility. In this work Ti-40Zr was produced by powder metallurgy in order to produce parts with complex geometry with high microstructural homogeneity to be applied in areas such as the space industry and surgical implants. Samples were produced by mixing of initial hydrided powders followed by uniaxial and cold isostatic pressing with subsequent densification by sintering between 800-1600 °C, in vacuum.

Contamination of titanium by oxygen is inevitable during its processing by powder metallurgy (PM). When dissolved interstitially in the crystal lattice of titanium, oxygen exerts a great influence on strength and other mechanical properties. In this paper we investigated the effects of milling and sintering of titanium hydride powders on the levels of oxygen in sintered samples. To minimize contamination, milling was carried out under argon atmosphere and the manipulation of powders was performed inside a glove box. Samples were milled at two different particles sizes, isostatically pressed and sintered at 1000°C and 1200°C. The results indicated that the oxygen content in the final samples is mainly influenced by the level of oxygen in the starting powders and the particle size of these powders.