International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

The microstructure and phase composition of Ti47,5Zr30,2Mn15,5V5Ho2 multiphase alloy and the phase composition of the hydrogenation product were investigated by scanning electron microscopy and X-ray phase analysis. It was established that holmium introduced into the alloy not only dissolves in the phase components of the eutectic, but also forms a new phase (oxide). The formation and further growth of crystals of holmium oxide occurs only on the surface of the crystallites of Laves phase. During the first hydrogenation the active absorption of hydrogen by the alloy occurred only when it was heated up to 520 °C, with hydrogen capacity of 2.62 wt.%. The hydrogenation product obtained after the saturation of the alloy with hydrogen contained a new phase, in addition to the hydrides based on the initial phases. After the sorption-desorption cycle, the alloy was already in the activated state and able to absorb hydrogen at room temperature and low pressure (0.21 MPa) starting from the first seconds of contact with the hydrogen medium.

The microstructure and phase composition of the eutectic alloy Ti47.5Zr30.2Mn22.5 obtained using titanium sponge, as well as the phase composition of hydrogenation product were investigated by scanning electron microscopy and X-ray phase analysis. It was found that when iodide titanium was completely replaced by titanium sponge, the alloy structure remained eutectic and consisted of bcc solid solution and Laves phase. It was shown that after a sorption-desorption cycle the alloy was in activated state and was capable to absorb hydrogen at room temperature and low pressure (0.21 MPa) starting from the first seconds of contact with hydrogen atmosphere, with hydrogen capacity of 2.61 wt.%.

Microstructure and mechanical properties of NiAl-Cr(Mo) eutectic alloy and the effect of 0.1Fe,1Nb,4Ti additions are investigated at room temperature (RT) and high temperature (1000°C). The alloys are prepared by arc melting method and then homogenized at 1300°C in Ar atmosphere for 24 h. In addition to the room temperature and high temperature compression tests and X-ray diffraction measurements, hardness measurements and microscopic analyses at room temperature are performed. NiAl-Cr(Mo) alloy exhibit fine cellular eutectic structure with coarse eutectic at interdendiric regions. However, the Nb and Ti addition reduced the formation of eutectic structure. Cr₂Nb-type Laves and Ni₂AlTi-type Heusler phases are observed in the XRD patterns of the Nb and Ti containing alloys respectively. Addition of Fe does not have important effect on the room and high temperature yield strength of the alloy, while the Nb and Ti increase the yield strength of the alloys at both temperatures.