In situ scattering study of multiscale structural evolution during liquid–liquid phase transition in Mg-based metallic glasses

Engineering Atomic-to-Nano Scale Structural Homogeneity towards High Corrosion Resistance of Amorphous Magnesium-Based Alloys

“…The differential scanning calorimetry (DSC) curve of Mg 65 Cu 15 Ag 10 Gd 10 amorphous alloys (Figure 1a) shows an abnormal exothermic peak that appeared after the glass transition temperature T g (422 K) [35]. The corresponding temperature was marked as T C (444 K), which, according to previous studies, is related to the liquid-liquid phase transition [28,36]. As the temperature continues to increase, a sharp exothermic peak starting at 458 K emerges, which can be assigned to the crystallization of the amorphous material [37].…”

“…The results further demonstrate that the Mg65Cu15Ag10Gd10 alloys remain the amorphous feature after TC treatment. Down to the nanoscale, an interference peak occurs in the TC-treated sample whereas it does not exist in the as-cast sample according to the results of SAXS (Figure 1c), which suggests the occurrence of nanoscale heterogeneity different from the amorphous matrix in the TC-treated sample [28,[38][39][40]. Furthermore, a spheroid model with polydispersity is employed to fit the SAXS profile of the TC-treated sample, and the obtained size distribution function result is displayed in Figure 1c inset [41,42].…”

“…Although local changes in structure and density are subtle and come with a small amount of heat release, it still makes remarkable differences in mechanical and functional properties [26,27]. Studies show that the liquid-liquid transition is closely related to the thermodynamic stability and mechanical properties of Mg-based amorphous alloys [28]. The thermodynamically-favored local order and loose structure emerge during the liquid-liquid transition, which benefits higher hardness and modulus than a completely disordered structure.…”

“…In addition, Hu et al [29] reveal that the metastable state formed during the liquid-liquid transition in (Fe 0.72 B 0.24 Nb 0.04 ) 95.5 Y 4.5 amorphous ribbon could significantly reduce the activation energy and reaction energy barrier of hightemperature oxidization. More importantly, by using synchrotron small-angle scattering, our group has demonstrated that the liquid-liquid phase transition can significantly impact the atomic-to-nano scale homogeneity in the medium-range structure of amorphous Mg alloys [28], which is strongly related to the corrosion resistance of the material [30][31][32][33]. This motivates us to fundamentally understand the correlation between liquid-liquid transition and corrosion, improving the corrosion resistance in amorphous Mg-based alloys.…”

Biodegradable Mg–Zn–Ca-Based Metallic Glasses

“…Recently, research enthusiasm is mushrooming in Mg-based alloys as biodegradable implants for biomedical application [ 1 , 2 , 3 , 4 , 5 ] for their multifaceted advantages. Firstly, Mg-based alloys exhibit high strength and comparable Young’s modulus to that of cortical bone.…”