Enhancement of cerium and hydrogen storage property of a low-cost Ti-V based BCC alloy prepared by commercial ferrovanadium

Based on the analysis of XRD, SEM, P-C-isotherm measurements and absorption kinetics simulation, it was indicated that Ce addition was an effective way to inhibit the formation of C14 Laves phase, improve flatness of the plateau, increase hydrogen diffusion rate and enlarge hydrogen storage capacity. The hydrogenation capacity of Ti27.25Cr28.05V37.25Fe7.45Ce1.0 alloy prepared by commercial ferrovanadium was 3.56 wt.% measured at 298 K. The dehydrogenation capacity was 2.25 wt.% and 2.54 wt.% measured at 343...

Effect of cerium content on microstructure and hydrogen storage performance of Ti_(24)Cr_(17.5)V_(50)Fe_(8.5)Ce_x(x=0-1.0) alloys

Effect of Ce addition on microstructure and hydrogen storage performance of Ti24Cr17.5V50Fe8.5Cex（x=0, 0.5at.%, 0.8at.% and 1.0at.%） alloys was studied by X-ray diffraction, scanning electron microscopy and P-C-isotherm measurements.The results indicated that Ce addition was a useful way to improve the flatness of the plateau and increase hydrogen storage capacity of Ti24Cr17.5V50Fe8.5 alloy.It was indicated that both homogenization of composition and increase of hydrogen diffusion coefficient were the main reasons for improving the hydrogen storage performance of Ti24Cr17.5V50Fe8.5Cex alloys.

Achieving high strength and ductility in high-entropy alloys via spinodal decomposition-induced compositional heterogeneity

The compositional heterogeneity in high-entropy alloys(HEAs)has been reported to be an inherent en-tity,which significantly alters the mechanical properties of materials by tuning the variation of lattice resistance for dislocation motion.However,since the body-centered cubic(BCC)structure is not close-packed,the change of lattice resistance is less sensitive to the normal concentration wave compared to that in face-centered cubic(FCC)structured materials.In this work,we selected a refractory bcc HEAs TiZrNbTa for the matrix and added a small amount of Al to facilitate the special spinodal decomposition structure.In particular,(TiZrNbTa)98.5 Al 1.5 displayed a typical basket-weave fabric morphology of spinodal decomposition structure with a characteristic periodicity of∼8 nm and had an optimal combination of strength and ductility(the yield strength of 1123±9 MPa and ductility of∼20.7%±0.6%).It was de-termined that by doing in situ TEM mechanical testing,the plastic deformation was dominated by the formation and operation of dislocation loops which provided both edge and screw components of dislo-cations.The synergetic effect of the remarkable chemical heterogeneity created by the spinodal decompo-sition and the spreading lattice distortion in high entropy alloys is quite effective in tuning the mobility of different types of dislocations and facilitates dislocation interactions,enabling the combination of high strength and ductility.