Significantly enhanced mechanical properties of ZrAlCo bulk amorphous alloy by microalloying with Ta

The alloy composition of Zr₅₄Al₁₇Co₂₉ with high glass forming ability (GFA) in the Zr-Al-Co system was predicted by using the multiple binary eutectic clusters from the phase diagram. Then the microalloying effects of Ta on the microstructure, thermal properties, mechanical properties, and corrosion resistance of (Zr₅₄Al₁₇Co₂₉)_100-xTa_x (x = 0, 1, 1.5, 2, 2.5, 3) bulk amorphous alloy (BAA) were systematically investigated. The alloy composition with 1 at.% Ta alloy can be cast into BAA rods with diameters of 4 mm. The (Zr₅₄Al₁₇Co₂₉)₉₉Ta₁ exhibited high yield stress of 2553 MPa, high fracture strength of 3170 MPa, plastic strain of 8.6%, and low Young's modulus of 111 GPa with better corrosion resistance in comparison with the ZrCuNiAl BAA, ZrCuAlAg BAA, and 316L stainless steel in the Hank's Balanced Salt solution. The Ni-, Cu-, Be-free (Zr₅₄Al₁₇Co₂₉)₉₉Ta₁ bulk amorphous alloys with a critical diameter up to 4 mm, excellent mechanical properties, superior corrosion resistance are believed to be useful in orthopedic applications.