Preparation, Characterization, and Properties of Novel Ti-Zr-Be-Co Bulk Metallic Glasses

We developed novel Ti-Zr-Be-Co bulk metallic glasses through Co addition based on a ternary Ti(45)Zr(20)Be(35) alloy. By altering the alloying routes and alloying contents, the influence of Co alloying on glass-forming ability, thermal stability, thermoplastic formability, crystallization behavior, and corrosion resistance has been investigated systematically. It was found that the best alloying route for enhancing the glass-forming ability, thermoplastic formability, compressive plasticity, and corrosion resistance is to replace Be by Co. Ti(45)Zr(20)Be(23)Co(12) possesses the largest critical diameter of 15 mm for glass formation. Ti(45)Zr(20)Be(27)Co(8) possesses the highest thermoplastic formability which is comparable to that of Vitreloy alloys. Ti(45)Zr(20)Be(25)Co(10) exhibits the largest room temperature plasticity of 15.7% together with a high specific strength of 3.90 × 10(5) Nm/kg. The addition of Co also strongly affects the crystallization behavior of the base alloy, resulting in a more complex crystallization process. The corrosion resistance of Ti-Zr-Be alloy in 1 mol/L HCl solution can also be enhanced by Co alloying. The related mechanisms have been explained in detail, which provide guidance for the composition design of Ti-based metallic glasses with improved properties.