Usually, monolithic bulk metallic glasses undergo inhomogeneous plastic deformation and exhibit poor ductility () at room temperature. We present a new class of bulk metallic glass, which exhibits high strength of up to 2265 MPa together with extensive “work hardening” and large ductility of 18%. Significant increase in the flow stress was observed during deformation. The “work-hardening” capability and ductility of this class of metallic glass is attributed to a unique structure correlated with atomic-scale inhomogeneity, leading to an inherent capability of extensive shear band formation, interactions, and multiplication of shear bands.
The effective fabrication of materials using selective laser melting depends on the process parameters. Here, we analyse the suitability of the energy density to represent the energy transferred to the powder bed, which is effectively used to melt the particles and to produce the bulk specimens. By properly varying laser power and speed in order to process the powder at constant energy density, we show that the equation currently used to calculate the energy density gives only an approximate estimation and that hatch parameters and material properties should be considered to correctly evaluate the energy density. GRAPHICAL ABSTRACT IMPACT STATEMENT Al-12Si SLM samples were fabricated at constant energy density. The laser power and laser scan speed combination variation was used to demonstrate the significant changes needed with energy density equation.
The compressive deformation and fracture features of Zr59Cu20Al10Ni8Ti3 bulk metallic glassy samples with aspect ratios in the range of 0.67–2.00 have been investigated. The compressive plastic strain of the glass monotonically increases with decreasing aspect ratio, but the maximum strength almost maintains a constant value of 1.77–1.88 GPa. All the compressive shear-band angles are equal to ∼40° if modified by the rotation of the primary shear bands.