This study investigates the effect of Ce content on the hydrogen storage properties of Ti_(0.98)Zr_(0.02)Mn_(1.5)Cr_(0.05)V_(0.43)Fe_(0.09)Ce_(x)(x=0,0.02,0.04,and 0.06,at%)alloys.Microstructural analysis of these all...This study investigates the effect of Ce content on the hydrogen storage properties of Ti_(0.98)Zr_(0.02)Mn_(1.5)Cr_(0.05)V_(0.43)Fe_(0.09)Ce_(x)(x=0,0.02,0.04,and 0.06,at%)alloys.Microstructural analysis of these alloys revealed dendritic microstructures without the segregation of chemical elements,with the C14 Laves phase identified as the dominant phase.After two activation cycles at 4 MPa and 293 K,the alloys exhibited excellent hydrogen absorption properties.The addition of Ce significantly improved the kinetics of the alloys.At x=0.02,the hydrogen absorption capacity reached 90%of its maximum within 137 s at 293 K.Pressure-composition-temperature curves indicated that hydrogen absorption capacity initially increased first and then decreased with increasing Ce content,reaching a maximum value of 1.85wt%at x=0.04.Thermodynamic results demonstrated that the enthalpy and entropy of hydrogen absorption followed a similar trend,which was consistent with the variation in hydrogen storage capacity.Thus,the improvement in hydrogen absorption capacity due to the addition of Ce is attributed to the increase in enthalpy.The increase of the lattice constant in the C14 Laves phase and the deoxidization effect of Ce are expected to be beneficial for the improvement of hydrogen absorption kinetics.展开更多
In order to research the different effects of Ce on as-cast microstructure of AZ91 magnesium alloy under different solidifi- cation rates, the die-cast samples with different diameters and different Ce contents were p...In order to research the different effects of Ce on as-cast microstructure of AZ91 magnesium alloy under different solidifi- cation rates, the die-cast samples with different diameters and different Ce contents were prepared, and some characteristics of as-cast microstructure were analyzed. The results showed that Ce could refine grain size, decrease the fraction of eutectic β-Mg17A112 phase, form A14Ce phase and decrease solid solution of A1 in the α-Mg matrix, but the above behaviors of Ce would be weakened under higher solidification rate. The essential reason for Ce to affect as-cast microstructure was that the Ce and A1 concentrated in the liquid phase in front of solid/liquid interface during solidification because Ce itself is difficult to solid solute in α-Mg matrix and inhibits solid solution of AI in α-Mg matrix. However, the dynamic condition of concentration of Ce, A1 would be changed when solidifica- tion rate varied, resulting in different influence extents of Ce on as-cast microstructure under different solidification rates.展开更多
基金financially supported by the National Key Research and Development Program of China (Nos.2023YFB3710401 and 2023YFB3710403)the State KeyLaboratory for Advanced Metals and Materials.
文摘This study investigates the effect of Ce content on the hydrogen storage properties of Ti_(0.98)Zr_(0.02)Mn_(1.5)Cr_(0.05)V_(0.43)Fe_(0.09)Ce_(x)(x=0,0.02,0.04,and 0.06,at%)alloys.Microstructural analysis of these alloys revealed dendritic microstructures without the segregation of chemical elements,with the C14 Laves phase identified as the dominant phase.After two activation cycles at 4 MPa and 293 K,the alloys exhibited excellent hydrogen absorption properties.The addition of Ce significantly improved the kinetics of the alloys.At x=0.02,the hydrogen absorption capacity reached 90%of its maximum within 137 s at 293 K.Pressure-composition-temperature curves indicated that hydrogen absorption capacity initially increased first and then decreased with increasing Ce content,reaching a maximum value of 1.85wt%at x=0.04.Thermodynamic results demonstrated that the enthalpy and entropy of hydrogen absorption followed a similar trend,which was consistent with the variation in hydrogen storage capacity.Thus,the improvement in hydrogen absorption capacity due to the addition of Ce is attributed to the increase in enthalpy.The increase of the lattice constant in the C14 Laves phase and the deoxidization effect of Ce are expected to be beneficial for the improvement of hydrogen absorption kinetics.
基金Projects supported by the Natural Science Foundation of Inner Mongolia(2013ZD10,2015MS0510)
文摘In order to research the different effects of Ce on as-cast microstructure of AZ91 magnesium alloy under different solidifi- cation rates, the die-cast samples with different diameters and different Ce contents were prepared, and some characteristics of as-cast microstructure were analyzed. The results showed that Ce could refine grain size, decrease the fraction of eutectic β-Mg17A112 phase, form A14Ce phase and decrease solid solution of A1 in the α-Mg matrix, but the above behaviors of Ce would be weakened under higher solidification rate. The essential reason for Ce to affect as-cast microstructure was that the Ce and A1 concentrated in the liquid phase in front of solid/liquid interface during solidification because Ce itself is difficult to solid solute in α-Mg matrix and inhibits solid solution of AI in α-Mg matrix. However, the dynamic condition of concentration of Ce, A1 would be changed when solidifica- tion rate varied, resulting in different influence extents of Ce on as-cast microstructure under different solidification rates.
