Abstract
The effects of heavy cold plastic deformation by rolling on microstructural features and mechanical properties of Ti–25Nb–6Zr–1.7Fe (wt %) biocompatible alloy (TNZF) were studied. After a preliminary alloy processing, a heavy plastic deformation by cold-rolling (CR) with a total relative degree of plastic deformation of 90% (equivalent plastic strain, ε = 2.42) and a subsequent solution heat treatment (CR+ST) at 900 °C for 0.6 ks/water quenching were applied and then investigated. The CR and CR+ST states have microstructures consisting of mixtures of β-Ti phases and α″-Ti. The alloy in CR state shows a pronounced deformation texture, with highly deformed and elongated β-Ti grains, exhibiting internal highly fragmented areas, with shear lines at about 45° and a sub-micron/nanocrystalline fine dispersed α″-Ti phase. The alloy in CR+ST state has completely recrystallized equiaxed polyhedral β-Ti grains, with average grain size close to 52 μm and a sub-micron/nanocrystalline fine dispersed α″-Ti phase. Recorded mechanical properties, for both CR and CR+ST states, show quite similar values for the yield strength (σ0.2), ultimate tensile strength (σUTS) and Vickers microhardness (HV0.1) for CR state (σ0.2 = 603 MPa, σUTS = 1282 MPa and 287 HV0.1) in comparison with CR+ST state (σ0.2 = 598 MPa, σUTS = 1256 MPa and 256 HV0.1). Values for the modulus of elasticity (E) are lower (E = 72 GPa for CR state and E = 61 GPa for CR+ST state) than those for conventional biocompatible alloys (E ~ 110 GPa).
Highlights
During the last decade, major efforts have been dedicated to studying multicomponent Ti alloys containing non-toxic and non-allergic alloying elements such as Nb, Zr, and Ta due to their appropriate combination of properties: good mechanical properties, high corrosion resistance in body fluids or simulated body fluids, and enhanced biocompatibility [1,2,3,4,5,6]
If one considers the mechanical properties, i.e., the demand for a low modulus of elasticity in implantable biomedical applications [7,8,9], it was demonstrated that the values of elastic modulus are strongly dependent on thermomechanical processing parameters [10,11,12]
The purpose of the present study is to examine the effects of heavy plastic deformation, applied by cold-rolling and followed by a solution heat treatment, on the microstructural features and mechanical properties of a Ti–25Nb–6Zr–1.7Fe alloy, to gain a larger perspective on the correlation between thermomechanical processing conditions and the properties that result
Summary
Major efforts have been dedicated to studying multicomponent Ti alloys containing non-toxic and non-allergic alloying elements such as Nb, Zr, and Ta due to their appropriate combination of properties: good mechanical properties, high corrosion resistance in body fluids or simulated body fluids, and enhanced biocompatibility [1,2,3,4,5,6]. A suitable thermomechanical processing route is a key issue in obtaining adequate microstructures containing a favorable phase combination to achieve a final desired combination of properties, i.e., low elastic modulus and suitable mechanical properties together with corrosion resistance and biocompatibility. Constituent phase fractions can be manipulated by thermomechanical processing to adequately steer the mechanical properties towards the desired values
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
