Formation, Thermal Stability and Deformation Behavior of High‐Strength Cu‐Based Bulk Glassy and Nanostructured Alloys

Cu₄₇Ti₃₃Zr₁₁Ni₈X₁ (X = Fe, Si, Sn) bulk glass‐forming alloys were prepared using arc melting and copper mold casting. Thermal analysis reveals an obvious glass transition and large supercooled liquid regions (ΔT_x = 50 – 57 K) for all alloys. The bulk glassy alloys possess good mechanical properties, including high yield stress (1818 – 2102 MPa) and fracture (1943 – 2186 MPa) strengths, Young's moduli of 67 – 109 GPa and large elastic strains of about 2.0 – 2.7 %. Only the Si‐containing alloy exhibits distinct strain hardening and plasticity (fracture strain of 4.4. %). This is due to a unique nanocomposite microstructure consisting of a uniform distribution of Cu‐rich nanoparticles embedded in the bulk amorphous matrix. The nanocomposite microstructure facilitates the formation of multiple shear bands that make the bulk glassy alloy resistant to crack propagation.