High glass forming ability correlated with microstructure and hydrogen storage properties of a Mg–Cu–Ag–Y glass

Abstract

Thermal characterization of an as-cast Mg 54 Cu 28 Ag 7 Y 11 bulk metallic glass revealed that this alloy exhibits excellent glass forming ability. High-resolution X-ray diffraction study and transmission electron microscopy show that heating and isothermal annealing treatment

Thermal, Microstructural and Electrochemical Hydriding Performance of a Mg65Ni20Cu5Y10 Metallic Glass Catalyzed by CNT and Processed by High-Pressure Torsion

“…The corresponding linear heating DSC thermogram exhibits typical features of a metallic glass, including the glass transition (T g = 439K), followed by a three-stage crystallization sequence characterized by T x1 = 471 K, T x2 = 579 K and T x3 = 648 K exothermic transformations (see Figure 2). The width of the supercooled liquid region obtained as ∆T x = T x1,onset − T g corresponds to a remarkably high GFA (∆T x = 32 K), in accordance with other Mg-based glasses [24]. The high value of ∆T x suggests that the undercooled liquid may have a strong resistance to crystallization either by thermal activation or by SPD.…”

“…The high value of ∆T x suggests that the undercooled liquid may have a strong resistance to crystallization either by thermal activation or by SPD. The apparent activation energy values of the T x1 , T x2 and T x3 crystallization transformations were determined from the slope of the Kissinger plot (see the inset of Figure 2), and the obtained values (E a,Tx1 = 210 kJ/mol, E a,Tx1 = 188 kJ/mol and E a,Tx1 = 312 kJ/mol) also indicate high thermal stability, with these values being slightly higher than those obtained for Mg 54 Cu 28 Ag 7 Y 11 [24]. The total enthalpy release (∆H) corresponding to the multi-step crystallization process is ∆H = 105 J/g.…”

“…The hydrogen storage performance of Mg-Ni-Y alloys can be improved by altering the addition of Ni and Y in order to nucleate a ternary eutectic 14H-LPSO phase; however, this long-period stacking ordered lamellar phase containing Ni and Y atoms does not form after dehydrogenation [23]. Highpressure hydrogen sorption experiments revealed that the as-cast fully amorphous Mg 54 Cu 28 Ag 7 Y 11 bulk metallic glass exhibits the largest enthalpy of hydrogen desorption compared to its partially and fully crystallized counterparts; therefore, it was assumed that the disordered local atomic structure of the glass is responsible for the hydrogen release [24]. It was found that the hydrogen storage capacity of fully amorphous meltspun Mg 85 Ni 15−x M x (M = Y or La) alloys and their partial devitrified state can exceed 5 wt.% at 300 • C [25].…”

High-Pressure Torsion of Non-Equilibrium Hydrogen Storage Materials: A Review

“…A complex transformation behaviour during hydrogen absorption/desorption was explored by in-situ X-ray synchrotron radiation of the Mg-Ni-La system, including a previously non-reported early stage formation of a La 2 Mg 17 H ~1.0 solid solution [113]. Detailed thermal characterization of a Mg 54 Cu 28 Ag 7 Y 11 BMG revealed that this composition has an excellent glass forming ability [114]. High pressure hydrogen-sorption experiments pointed out that the as-cast fully amorphous alloy exhibits the largest enthalpy of desorption, compared to the partially and fully crystallized states having similar concentrations.…”

“…High pressure hydrogen-sorption experiments pointed out that the as-cast fully amorphous alloy exhibits the largest enthalpy of desorption, compared to the partially and fully crystallized states having similar concentrations. Since the fully crystallized sample does not desorb hydrogen at all, it can be assumed that the disordered local atomic structure of the glass is accountant for the hydrogen release [114].…”