Effect of Nb on $\beta \to {\alpha }^{″}$ Martensitic Phase Transformation and Characterization of New Biomedical Ti-xNb-3Fe-9Zr A

Abstract

A new generation of Ti-xNb-3Fe-9Zr ( x = 15 , 20, 25, 30, 35 wt %) alloys have been designed using various theoretical approaches including DV-xα cluster, molybdenum equivalency, and electron to atom ratio. Afterward, designed alloys are fabricated using cold crucible levitation melting technique. The microstructure and mechanical performances of newly designed alloys are characterized in this work using scanning electron microscope and universal testing machine, respectively. Each alloy demonstrates monolithic β phase except Ti-35Nb-3Fe-9Zr alloy which display dual α ″ + β phases. Typically, niobium acts as an isomorphous beta stabilizer. However, in this work, formation of martensitic α ″ phases occurs at 35 wt % of niobium among the series of newly designed alloys. Furthermore, none of the alloys fail till the maximum load capacity of machine, i.e., 100 KN except Ti-35Nb-3Fe-9Zr alloy. Moreover, the Vickers hardness test is carried out on Ti-xNb-3Fe-9Zr alloys which demonstrate slip bands around the indentation for each alloy. Notably, the deformation bands and cracks around the indentations of each alloy have been observed using optical microscopy; Ti-35Nb-3Fe-9Zr demonstrates some cracks along with slip bands around its indentation. The Ti-25Nb-3Fe-9Zr alloy shows the highest yield strength of 1043 ± 20 MPa , large plasticity of 32 ± 0.5 % , and adequate hardness of 152 ± 3.90 Hv among the investigated alloys. The Ti-25Nb-3Fe-9Zr alloy demonstrates good blend of strength and malleability. Therefore, Ti-25Nb-3Fe-9Zr can be used effectively for the biomedical applications.

Effects of Thermo-Mechanical Processing on the Microstructure and Mechanical Properties of β -Type Titanium Alloys

“…[23] The solution treatment after cold rolling leads to a gradual increase in the hardness values of TNTZ with an increase in the duration of the solution treatment due to the martensite phases. [24] The HV values are, ~204 HV for CST10Q, ~229 HV for CST30Q, and ~242 HV for CST60Q, respectively.…”

Unravelling Role of the Microwave Sintering Effects on Microstructure, Density, and Corrosion Behavior of porous Ti-13.3at.% Nb Shape Memory Alloys

“…Conversely, Ti-based shape memory alloys containing a Nb content ranging from 11 to 29 at.% exhibit a thermoelastic martensitic transformation from the β → α ́ phase [18,19].It is worth noting that Nb acts as a stabilising element, lowering the temperatures at which martensitic transformations occur [20]. As a result, at ambient temperature, the functional characteristics of Ti-Nb shape memory alloys demonstrate a notable transition from a form memory effect to superelasticity [21].…”