Solute lean Ti-Nb-Fe alloys: An exploratory study. (January 2017)

• Record Type: Journal Article
• Authors: Salvador, Camilo A.F.; Dal Bó, Mariana R.; Costa, Fernando H.; Taipina, Marcia O.; Lopes, Eder S.N.; Caram, Rubens
• Is Part Of: Journal of the mechanical behavior of biomedical materials. Volume 65(2017)
• Page Start: 761
• Page End: 769
• Publication Date: 2017-01
• Subjects: Titanium alloys -- Alloy design -- Quenching -- Phase transformations -- Mechanical properties; Biomedical materials -- Periodicals; Biomedical materials -- Mechanical properties -- Periodicals; Biomedical materials; Biomedical materials -- Mechanical properties; Periodicals; Electronic journals; 610.28
• DOI: 10.1016/j.jmbbm.2016.09.024
• Languages: English
• ISSNs: 1751-6161

Abstract

Abstract: In this study, we explored the Ti-Nb-Fe system to find an optimal cost-effective composition with the lowest elastic modulus and the lowest added Nb content. Six Ti-(31-4x)Nb-(1+0.5x)Fe ingots were prepared and Nb was substituted with Fe, starting at Ti-31Nb-1.0Fe and going up to Ti-11Nb-3.5Fe (wt%). The ingots were subjected to cold rolling, recrystallization and solution treatment, followed by water-quenching (WQ), furnace cooling (FC) or step-quenching to 350 °C, which caused massive formation of isothermal ω phase. All the water-quenched alloys displayed athermal ω phase, which is apparently the result of fully collapsed β phase. The Fe content improved the compressive strength of the alloys. In the FC alloys, substitution with Fe favored the formation of α phase instead of ω phase, giving rise to a solute-rich β phase with a lattice parameter of 0.3249 nm. Among the FC alloys, the lowest modulus of 83±4 GPa was obtained in the Ti-19Nb-2.5Fe alloy, which exhibited fine and well dispersed α precipitation and absence of ω phase. DSC experiments indicated that the experimental alloys showed varying phase stability during heating. Graphical abstract: Highlights: Six solute lean Ti-Nb-Fe alloys (from 31Nb-1.0Fe to 11Nb-3.5Fe) were prepared. Omega phase was detected via TEM among all solution-treated, water-quenched alloys. Fe enhances mechanical strength due to solid solution effect. The experimental alloys showed varying phase stability during heating. On continuous cooling, Fe favors the α phase formation instead of iso ω phase.