Diffusion during Powder Metallurgy Synthesis of Titanium Alloys

Abstract

In the present study titanium alloys were synthesized by the blended elemental press-andsinter powder metallurgy approach using hydrogenated titanium powder. Experimental investigation and modeling of the homogenization processes during synthesis were used to analyze peculiarities of mass transfer and factors affecting diffusion. Processes of alloying elements redistribution during chemical homogenization of powder blends are shown to be strongly dependent on the chemical composition of the initial powders. Optimization of the processing parameters allows to synthesize uniform, nearly-dense material with reduced grain size, at relatively low temperatures and short time. This will provide improvement of mechanical properties simultaneously with better cost-effectiveness of the process.

The effect of cooling rates on the microstructure and mechanical properties of thermo-mechanically processed Ti–Al–Mo–V–Cr–Fe alloys

“…The obtained sintered density was close to ~99 % by using Ti powders containing 3 wt. % hydrogen [19]. This is considered to be the lowest cost powder metallurgy technique.…”

Efecto de las variables de proceso sobre el comportamiento a flexión de aleaciones Ti - 3% at. X (X = Nb, Ta) obtenidas por pulvimetalurgia

“…Una posible explicación es el aumento de la reacción del titanio con la bandeja soporte así como el aumento de la difusión del oxí-geno en borde de grano. El efecto del oxígeno es más perjudicial en las aleaciones alfa más beta que en el titanio puro, por la mayor cantidad de bordes de grano generados durante la difusión del elemento betá-geno [6] . En cuanto a las interacciones cruzadas de varios factores, los valores negativos indican un efecto combinado perjudicial al combinar ambos factores.…”

“…No obstante, la utilización de una temperatura más baja limita la difusión en estado sólido y puede ser un inconveniente importante para este tipo de aleaciones beta [4][5][6] .…”

Powder metallurgy of titanium – past, present, and future

“…Since 2000, a significant amount of work regarding vacuum sintering of hydrogenated Ti powder has been reported by Ivasishin et al [147,170,175,[192][193][194][195][196] and Savvakin et al [197] It has been reported that a blend of Ti hydride with 10 wt-% 60Al/40V master-alloy powder produced Ti-6Al-4V with 98.5-99.5% TD in the as-sintered state, versus 90-95% when metallic Ti powder was used [193]. Additionally, it has been reported that using Ti hydride produced samples with an as-sintered oxygen content of 0.21 versus 0.39 wt-% when metallic Ti powder was used [198].…”