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Cu46Zr47Al7 bulk metallic glass (BMG) and its composites in plate with different thicknesses up to 6 mm were prepared by copper mold casting. Primary crystallizing phases with different microstructures and volume fractions could be obtained under different cooling rates, forming some composites with different mechanical properties. Under compression tests, the 2-mm-thick monolithic BMG has a yield strength of 1894 MPa and a high fracture strength of up to 2250 MPa at plastic strain up to 6%, exhibiting apparent “work-hardening” behavior. The 4-mm-thick Cu46Zr47Al7 BMG composite containing martensite phase yields at 1733 MPa and finally fails at 1964 MPa with a plastic strain of 3.7%.

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The compressive properties and the Vickers hardness of Cu-, Fe-, Mg-, and Zr-based monolithic bulk metallic glasses (BMGs) as well as Ti-based nanostructure-dendrite composites were investigated and compared. The monolithic BMGs exhibit nearly the same yield strength σ y and fracture strength σf but poor plasticity. The Vickers hardness HV of the monolithic BMGs follows the empirical relationship HV/3 ≈σy ≈σf. The Ti-based composites yield at a relatively low stress level (less than 850 MPa) but fail at a very high fracture stress (∼ 2 GPa) and exhibit a large strain hardening ability. Accordingly, the Vickers hardness HV of the Ti-based nanostructure-dendrite composites obeys the relationship σy <HV/3 <σf. Based on these results, the relationship between the Vickers hardness and the compressive properties of the investigated materials will be discussed by taking the yield and fracture strength (σ y and σf), the strain hardening exponent n, and the elastic and plastic energy stored upon deformation (δΕ and δP) into account.