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To identify the structural role of alloying element M (M = Ti, Ga, Co, Fe) on the glass-forming ability (GFA) of Cu 50Zr 50 base alloy, the atomic structures of the binary and ternary metallic glasses were examined by extended X-ray absorption fine structure (EXAFS) spectroscopy. The EXAFS curve-fitting analysis indicates that the main structural difference among the metallic glasses is in the atomic packing density of Cu-centered clusters. The relative shortening of the Cu–M distance is closely related to the heat of mixing between Cu and M: the more negative the heat of mixing, the larger is the shortening of the Cu–M distance. Based on a systematic analysis of the component properties and GFA data for Cu–Zr based alloys, it is suggested that alloying elements that bring a more uniform distribution of atomic size and possess strong chemical interactions with the main components should be selected in developing large-size bulk metallic glasses. [ABSTRACT FROM AUTHOR]

Focuses on the significance of conducting indentation tests for determining the microhardness and fracture toughness of materials. Assessment of the Vickers hardness of thermal spray coatings considering measurement locations, directions, and indenter loads; Utilization of thermal sprayed Cr3C2-NiCr coatings in high temperature applications such as in turbine engine and steel industry; Examination of the wear behavior of the coating.

The crystallization kinetics of Zr60Al15Ni25 bulk glassy alloy under isochronal and isothermal conditions has been investigated by differential scanning calorimetry (DSC). The microstructure of as-cast Zr60Al15Ni25 bulk glassy alloy is observed by high-resolution electron microscopy (HREM). It is found that there exist nanocrystals with a size of about 7 nm in the glassy matrix, which are not observed in the XRD image. The results of Kissinger analysis show that the effective activation energies for glass transition (457 kJ/mol) and crystallization (345 kJ/mol) are high, indicating that it has large thermal stability against crystallization. The crystallization of Zr60Al15Ni25 bulk glassy alloy under isothermal annealing can be modeled by the Johnson-Mehl-Avami equation. The crystallization kinetics parameters show that the isothermal crystallization starts from the growth of the pre-existing nanocrystals and the crystallization process is diffusion-controlled. [ABSTRACT FROM AUTHOR]