Characteristics of cast Ti53.3-xNb10Zr10Ni10Co10Fe6.7Bx compositionally complex alloys

In the current investigation, elemental boron was added to form a series of Ti 53.3-x Nb 10 Zr 10 Ni 10 Co 10 Fe 6.7 B x Compositionally Complex Alloys (CCAs). Alloying was done via vacuum arc melting in amounts of 0.0, 5.3, and 10.6 at.%. From the thermodynamic parameters, adding B to the base alloy increased the system’s entropy. The microstructure of the prepared CCAs was characterized using scanning electron microscopy, transmission electron microscopy, and X-ray diffraction (XRD). The mechanical properties of CCAs as related to microstructure were assessed. According to XRD results, B-based intermetallic phases were obtained in the prepared CCAs, which were binary as Ti 3 B 4 and ZrB 2 and ternary as FeNbB and Nb 3 Co 4 B 7 . These intermetallic phases notably provided strengthening effects to the B-added alloys. Ti 48 Nb 10 Zr 10 Ni 10 Co 10 Fe 6.7 B 5.3 CCA showed the most homogenous microstructure obtained by the arc melting process. Adding B increased Young’s modulus from 141 GPa (without B) to 195 GPa and 260 GPa with 5.3 and 10.6 at.%B, respectively. Hardness also increased from 502 to 606 HV with 5.3 at.% B and to 648 HV with 10.6 at.%B. Accordingly, the wear resistance increased with B addition where 10.6 at.%B sample showed the lowest wear rate among the other conditions. However, 5.3 at.% B was nominated as the optimum addition amount due to its notable microstructure homogeneity.