title: Influence of Nb on the β→α″ martensitic phase transformation and properties of the newly designed Ti-Fe-Nb alloys.
abstract: A series of Ti-7Fe-xNb (x=0, 1, 4, 6, 9, 11 wt.%) alloys was designed and cast to investigate the β→α″ martensitic phase transformation, β phase stability, the resulting microstructure and mechanical properties. Phase analysis revealed that only Ti-7Fe-11Nb alloy shows a single body-centred cubic β phase microstructure while the others are comprised of β and orthorhombic α″ phases. Moreover, Nb addition up to 11 wt.% enhances the stability and volume fraction of β phase in the microstructure, hence reducing the propensity of the alloy system to form α″ phase during quenching. Compressive yield strength and hardness of the alloys are (985-1847) MPa and (325-520) Hv respectively. Additionally, Ti-7Fe-11Nb possesses the lowest Young's modulus (84 GPa) and the highest deformability (42% strain) among the designed alloys due to the single β phase microstructure. This high deformability is also corroborated by the large plastic deformation zone underneath the Vickers indenter. In contrast, the fractured surfaces of Ti-7Fe and Ti-7Fe-1Nb alloys after compressive tests mostly contain shallow dimples, verifying their low ductility. The good combination of mechanical properties obtained for Ti-7Fe-11Nb renders it more desirable than commonly used CP-Ti and Ti-6Al-4V materials and makes it a promising candidate for biomedical application.
authors.affiliation: School of Engineering, Edith Cowan University, 270 Joondalup Drive, Joondalup, Perth, WA 6027, Australia. Electronic address: sehtemam@our.ecu.edu.au.
authors.forename: Shima
authors.initials: S
authors.lastname: Ehtemam-Haghighi
authors.affiliation: School of Engineering, Edith Cowan University, 270 Joondalup Drive, Joondalup, Perth, WA 6027, Australia.
authors.forename: Yujing
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Materials Engineering, Shanghai Key Laboratory of Modern Metallurgy and Materials Processing, Shanghai University, 149 Yanchang Road, Shanghai 200072, China.
authors.forename: Guanghui
authors.initials: G
authors.lastname: Cao
authors.affiliation: School of Engineering, Edith Cowan University, 270 Joondalup Drive, Joondalup, Perth, WA 6027, Australia. Electronic address: l.zhang@ecu.edu.au.
authors.forename: Lai-Chang
authors.initials: LC
authors.lastname: Zhang
mesh_terms: D000497:Alloys / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D008422:Materials Testing; D009556:Niobium / Q000737:chemistry*; D013718:Tensile Strength; D014025:Titanium / Q000737:chemistry*
chemical_list: D000497:Alloys; D009556:Niobium; D014025:Titanium; D007501:Iron
keywords: Mechanical property; Microstructure; Phase stability; Shear bands; Titanium alloy