In Situ Scattering Studies of Crystallization Kinetics in a Phase-Separated Zr–Cu–Fe–Al Bulk Metallic Glass

Thermal stability and the crystallization kinetics of a phase-separated Zr–Cu–Fe–Al bulk metallic glass were investigated using in situ high-energy synchrotron X-ray and neutron diff raction, as well as small-angle synchrotron X-ray scattering. It was revealed that this glass with excellent glass-forming ability possesses a two-step crystallization behavior. The crystalline products and their evolution sequence are more complicated than a homogeneous Zr–Cu–Al glass with average glass-forming ability. The experimental results indicate that a fi nely distributed nanometer-sized cubic Zr2 Cu phase forms fi rst and then transforms to a tetragonal Zr2 Cu phase, while the matrix transforms to an orthorhombic Zr3 Fe phase. The strength of the Zr–Cu–Fe–Al composite containing cubic Zr2 Cu phase and glass matrix increases, and the plasticity also improves compared to the as-cast Zr–Cu–Fe–Al bulk metallic glass. Our results suggest that the formation of multiple and complex crystalline products would be the characteristics of the Zr–Cu–Fe–Al glass with better glass-forming ability. Our study may shed light on the synthesis of bulk-sized glass–nanocrystals composites of high strength and good plasticity.