Plasticity of bulk metallic glasses improved by controlling the solidification condition

Abstract

Different bulk metallic glasses (BMGs) were prepared in ductile Cu_47.5Zr_47.5Al₅, Zr₆₂Cu_15.4Ni_12.6Al₁₀, and brittle Zr₅₅Ni₅Al₁₀Cu₃₀ alloys by controlling solidification conditions. The achieved microstructures were characterized by x-ray diffraction, differential scanning calorimetry, transmission electron microscopy, and synchrotron- based high-energy x-ray diffraction. Monolithic BMGs obtained by high-temperature injection casting are brittle, while BMGs bearing some nanocrystals with the size of 3 to 7 nm and 2 to 4 nm, obtained by low-temperature injection casting and in situ suction casting, respectively, exhibit good plasticity. It indicates that the microstructures of BMGs are closely affected by the solidification conditions. Controlling the solidification conditions could improve the plasticity of BMGs.

Appendix

FIG. A1

Synchrotron XRD patterns of the HT sample of Cu_47.5Zr_47.5Al₅ alloy, indicating that HT sample is monolithically amorphous.

TABLE AI

Glass-transition temperature(T_g), onset crystallization temperature(T_x) and crystallization enthalpy(E_cryst.) of the samples of Cu_47.5Zr_47.5Al₅, Zr₆₂Cu_15.4Ni_12.6Al₁₀, and Zr₅₅Ni₅Al₁₀Cu₃₀ prepared by HT, LT, and SC.

FIG. A2

Physical XRD patterns of the HT sample of Cu_47.5Zr_47.5Al₅ alloy, converted from the patterns recorded using a two-dimensional image plate detector (Fig. A1).

FIG. A3

Nominal stress–strain curves of HT, LT, and SC samples of (a) Zr₅₅Ni₅Al₁₀Cu₃₀ and (b) Zr₆₂Cu_15.4Ni_12.6Al₁₀. They compressed in a constant strain rate of 4 × 10⁻⁴ s⁻¹. They show different mechanical behaviors for three different samples, brittleness for HT, and plasticity for LT and SC.