Ultrahigh strength and large plasticity of nanostructured Ti62Nb12.2Fe13.6Co6.4Al5.8 alloy obtained by selectively controlled micrometer-sized phases

• Published in: Materials characterization Vol. 124; pp. 260 - 265
• Main Authors: Liu, L.H., Yang, C., Liu, Z.Y., Zhang, L.C., Zhang, W.W., Huang, X.S., He, L.J., Li, P.J.
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.02.2017
• Subjects: Mechanical properties; Rapid solidification; Semi-solid sintering; Titanium alloys; Mechanical properties; Titanium alloys; Semi-solid sintering; Rapid solidification
• ISSN: 1044-5803; 1873-4189
• DOI: 10.1016/j.matchar.2017.01.009

We report that the strength and plasticity of Ti62Nb12.2Fe13.6Co6.4Al5.8 alloy can be modulated by selectively controlled micron-sized phases, i.e. β-Ti phase and twined (CoFe)Ti2 phase. It is found that the alloy with micron-sized β-Ti phase embedded in nanostructured matrix possesses lower yield strength but higher ultimate strength relative to the alloy with micron-sized (CoFe)Ti2 phases. The plastic strain and ultimate strength of the alloy with micron-sized β-Ti phases is as large as 22.1% and 2826MPa, respectively. The work-hardening exponent n of the alloy with micron-sized β-Ti phase, 0.12, is far greater than 0.008 for the alloy with (CoFe)Ti2 phase. Such significant and different mechanical properties are attributed to the roles and response of micron sized phases during deformation process. [Display omitted] •Nanostructured Ti62Nb12.2Fe13.6Co6.4Al5.8 alloy with excellent mechanical property was fabricated.•Deformation mechanism of the nanostructured alloy with different micron-sized phases is proposed.•Micron sized phases during deformation play a key role on work-hardening behavior.