Effect of Thermo-Mechanical Treatments on the Microstructure and Mechanical Properties of the Metastable beta-type Ti-35Nb-7Zr-5Ta Alloy

Author(s)

Plaine, Athos Henrique ^[1] ; da Silva, Murillo Romero ^[1] ; Bolfarini, Claudemiro ^[1]

Affiliation

^[1] Univ Fed Sao Carlos, Dept Engn Mat, Rod Washington Luis Km 235, BR-13565905 Sao Carlos, SP - Brazil

• Document type: Journal article
• Source: MATERIALS RESEARCH-IBERO-AMERICAN JOURNAL OF MATERIALS; v. 22, n. 1 2019.
• Web of Science Citations: 0

Abstract

In this work, theoretical composition design and thermo-mechanical treatments were combined in order to improve the mechanical compatibility of a biomedical beta-type titanium alloy. By applying a composition design theory, cold rolling and low temperature aging, a metastable beta-type Ti-35Nb-7Zr-5Ta (wt%) alloy with an elastic modulus of 47 GPa and a yield strength of 730 MPa was successfully fabricated. This combination of high yield strength and low elastic modulus resulted in enhanced elastic recoverable strain of 1.7%, which is much higher than that of the conventional metallic biomaterials. The microstructure responsible for the much sought-after mechanical properties was observed to be mainly consisted of a homogeneous distribution of nanometer-sized omega- and alpha-precipitates in a beta-phase matrix obtained via cold rolling plus short-time aging at low temperature, i.e. aging at 673 K for 20 min. These precipitates increase the strength of the material by hindering the motion of dislocations while the beta-matrix with relatively low content of beta-stabilizers gives rise to the observed low elastic modulus. By extending aging time, a higher strength is reached at the expense of an undesirable increasing in elastic modulus. (AU)

• FAPESP's process: 16/17502-7 - Development and characterization of new titanium alloys for biomedical stent applications
• Grantee: Athos Henrique Plaine
• Support Opportunities: Scholarships in Brazil - Post-Doctoral