ABSTRACT
The effect of the substitution of Ti by Zr on the crystal structure, microstructure, and first hydrogenation behavior of Ti2-xZrxCrV where X = 0.5, 1.0, 1.5, and 2.0 have been investigated. The samples were synthesized by arc-melting and characterized by X-ray diffraction, scanning electron microscopy, and energy-dispersive spectroscopy. The hydrogenation capacity was measured using a home-made Sieverts apparatus. Pure-Ti2CrV crystallizes in a body-centered cubic structure (BCC). Substitution of Ti by Zr leads to the appearance of a secondary phase, namely a C15 Laves phase for the Ti-containing samples, and C15 Laves phase plus a Zr-rich phase for the X = 2.0 sample. The substitution of Ti by Zr increased the lattice parameters in both phases for all samples. Increasing Zr content made the first hydrogenation faster but reduced the hydrogen capacity.
ABSTRACT
In this work, the hydrogen storage behavior of Ti2CrV + X wt.% Zr3Fe, where X = 2, 4, 6, 8 and 10 was investigated. The synthesis of all samples was carried out through arc-melting, followed by comprehensive characterization using X-ray diffraction, scanning electron microscopy, and energy-dispersive spectroscopy. The pure-Ti2CrV as-cast sample presented a single-phase microstructure. However, the addition of the Zr3Fe led to a remarkable transformation, resulting in the appearance of a Zr-rich secondary phase. It was found that the first hydrogenation is improved with the addition of at least 6 wt% of Zr3Fe, avoiding any preheating of the sample. These samples achieved their maximum capacity in approximately 10 min at room temperature. The maximum capacity recorded was 4.2 wt% H for the sample with X = 6 wt% Zr3Fe, while for X = 8 and 10 wt% Zr3Fe, the capacity recorded was 4.1 wt% and 4.0 wt%, respectively.
ABSTRACT
The study of powder metallurgy processing methods for titanium represents a promising avenue that can respond to a growing demand. This work reports the feasibility of direct powder forging (DPF) as a method to process large spherical Ti-6Al-4V powder into wrought products with noteworthy properties and physical characteristics. Direct powder forging is a thermomechanical process that imparts uniaxial loading to an enclosed and uncompacted powder to produce parts of various sizes and shapes. Stainless steel canisters were filled with prealloyed Ti-6Al-4V powder and consolidated through a multi-step open-die forging and rolling process into wrought DPF bars. After DPF, annealing was performed in the upper α+ß phase. The results show that full consolidation was achieved and higher mechanical properties than the Ti-6Al-4V grade F-23 requirements in annealed conditions were obtained. The results also show that direct powder forging of spherical titanium powder could produce wrought mill products and exhibit some potential for further investigation for industrial applications.