Abstract
? 2022 Elsevier B.V.The present study reports the effect of substituting Zr with Sc on the glass forming ability (GFA) and mechanical properties of ZrCuNiAlTi bulk metallic glass (BMG). Results showed that Zr57-xCu20Ni8Al10Ti5Scx (x = 0, 1, 2, 3, 4 at%) BMGs had the best GFA at x = 2, and the critical size was 10 mm, which correlated well with the GFA indicator (Trg and γ). The large atomic radius of Sc and small Gibbs free energy difference between the supercooled liquid and crystalline solid (ΔGl-c) caused significant atomic size mismatch and inhibited crystallization during cooling, ultimately improving GFA. Compression test results indicated that the plasticity of the Zr55Cu20Ni8Al10Ti5Sc2 BMG increased fivefold (9.1%) relative to that of the Sc-free case, whereas fracture stress was successfully retained at a value of 1815 MPa. The high plastic strain of Zr55Cu20Ni8Al10Ti5Sc2 BMG can be attributed to the localized nanocrystallization phenomenon under uniaxial compression and to the high relaxed excess free volume (REFV) in ZrCuNiAlTiSc BMGs. The high REFV prevented the expansion of shear bands, generated secondary shear bands, and finally increased plasticity.
NSTL
Elsevier