New Cu-Based Bulk Metallic Glasses with High Strength of 2000 MPa

New Cu-based bulk amorphous alloys exhibiting a large supercooled liquid region and good mechanical properties were formed in a quaternary Cu-Ni-Zr-Ti systems consisting of only metallic elements. The compositional range for the formation of the amorphous alloys that have high glass forming ability (GFA) (> 3 mm diameter) and large supercooled liquid region (> 50 K) is defined in the pseudo-ternary phase diagram Cu-Ni-(Zr, Ti). A bulk amorphous Cu₅₄Ni₆Zr₂₂Ti₁₈ alloy with the diameter of 6 mm can be prepared by copper mold casting. The Cu₅₄Ni₆Zr₂₂Ti₁₈ alloy shows glass transition temperature (T_g) of 712 K, crystallization temperature (T_x) of 769 K and supercooled liquid region (ΔTx) of 57 K. The Cu₅₄Ni₆Zr₂₂Ti₁₈ alloy exhibits high compressive fracture strength of about 2130 MPa with a plastic strain of about 1.5 %. The new Cu-based bulk amorphous alloy with high GFA and good mechanical properties allows us to expect the extension of application fields as a new engineering material.