Improved mechanical properties and corrosion resistance of Zr-Cu-Al-Ni-Ti bulk metallic glasses by Co addition

Zr-based bulk metallic glasses (BMGs) are considered very promising medical materials because of their high strength and good corrosion resistance. However, poor room temperature plasticity severely hinders their development. In this work, a series of Zr61Cu18Al9Ni7-xTi5Cox (x = 0,1,3,5,7 at.%) BMGs are manufactured using vacuum arc melting technology. The effect of the Co addition on the glass forming ability, mechanical properties, and corrosion resistance is investigated. The results show that the appropriate Co addition can improve the room temperature plasticity and corrosion resistance. Compression tests show that when 1 at.% of Co element is added, the compressive strength is 1769.0 MPa, and the plasticity is 11.5 %, higher than the base alloy Zr61Cu18Al9Ni7Ti5 with 1607.9 MPa and 3.4 %. Corrosion tests show that the passivation interval of all Zr-based BMGs increases with the addition of Co. In particular, the maximum passivation interval of 1.320 V and the minimum self-corrosion current density are exhibited at 5 at.% Co addition. Overall, the effects of Co addition in terms of mechanical and corrosion aspects provide new guidance for the study of Zr-based alloys in the medical field.