V-Free Ti-6Al-7Nb alloy may be an interesting candidate as a substitute to the traditional Ti-6Al-4V alloy on development of biomedical components. The inspection of surface integrity through digital microscopy techniques shows strong potential for comparative analysis and optimization of manufacturing processes. This work deals with the comparative analysis of turned surfaces of dual-phase (α+β) titanium alloys: Ti-6Al-4V and Ti-6Al-7Nb, under different cutting conditions. Digital image processing and analysis technique has been used to evaluate the volume fraction of phases and their distribution. An innovative methodology for digitizing the surface topography was applied, based on the association of modern microscopy techniques with digital image processing-Correlative Microscopy. The global outcomes show that Ti-6Al-4V samples presented better homogeneity, with a mean β volume fraction of about 17%, compared to 11% of Ti-6Al-7Nb samples. Combination of higher feed rate and lower velocity produce rougher topography for both alloys, while the topographic formation obtained by the combination of lower feed rate and higher velocity seems smoother. In addition, Ti-6Al-4V alloy presents rougher topography in comparison topography of Ti-6Al-7Nb, under all conditions, probably due to the different phase distribution. The correlative microscopy allowed a correspondence between the cutting conditions and the microstructural properties of the both Ti-6Al-4V and Ti-6Al-7Nb alloys, through the analysis of the machined surface.
Ti6Al4V alloy is a well-known difficult-to-cut material used in different industrial applications, to achieve the expected component quality, proper definition and control of the machining process parameters must be accomplished. To address this problem, simulations with finite element method (FEM) seem to be an interesting engineering tool to model and optimize machining processes. Nevertheless, the model capability in capturing the behaviour observed in real machining processes is associated with the definition of the model and parameters that describe the workpiece flow stress. This contribution aimed to study the performance of built-in AdvantEdge-2D™ material laws applied in Ti6Al4V orthogonal cutting simulations under dry conditions. The numerical models were created under three levels of cutting speed, a constant feed rate and depth-of-cut, a variable tool rake angle (of 20° and −6°/0°), but also using four Ti6Al4V constitutive laws, namely, one suggested in AdvantEdge™ library, a Johnson-Cook (JC) model, a Power law (PL) and a PL coupled with ductile damage model. Experimental results were used to assess the numerical models’ accuracy in predicting the machining forces and metal chips. Satisfactory results regarding the machining forces prediction were achieved with all material laws, yet when the damage criterion was coupled with the constitutive laws (PLD and AE standard material law), the simulations were also were able to achieve the expected chip morphology (serrated metal chips).
CNC machining manufacturing is critical to the development of biomedical industries, especially orthopaedic implants. Understanding a material's machinability under different cutting conditions is essential for component design as well as for optimizing the machining process. Despite their widespread use in the biomedical industry, α + β-type titanium (Ti) alloys, such as Ti-6Al-4V and Ti-6Al-7Nb, are being replaced by β or near β-type Ti alloys like Ti-13Nb-13Zr Ti alloy due to issues associated with Vanadium and Aluminium toxicity and lower modulus of elasticity. By simulating the machining of a functional cone of the hip prosthesis femoral component, this work aims to investigate some aspects of the machinability of titanium alloys: Ti-6Al-4V, Ti-6Al-7Nb, and Ti-13Nb-alloy 13Zr. Cutting forces values were registered during the tests. Using correlative microscopy, machined surfaces were examined by measuring roughness and topographic examination. According to the results obtained, the new titanium alloy Ti-13Nb-13Zr alloy presents lower cutting forces and a worse surface finish for a lower feed rate. However, when the feed rate was increased to double the initial value, this alloy had the smallest increase in Ra, compared with the other alloys under test The effect of federate is highly significant in cutting forces and surface finish, with increases in cutting forces of 35%, 45% and 66% on cutting forces for Ti-13Nb-13Zr, Ti-6Al-4V and Ti-6Al-7Nb, respectively.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.