Effect of Fe content, sintering temperature and powder processing on the microstructure, fracture and mechanical behaviours of Ti-Mo-Zr-Fe alloys

[EN] The present work studies the effect of iron on the microstructural characterization and mechanical properties of Ti12Mo6ZrxFe alloys that fabricated by two different techniques elemental blend (EB) at 600 MPa and mechanical alloying (MA) at 600 MPa and 900 MPa with different sintering temperatures. The Ti12Mo6ZrxFe (x = 1, 2, 3 and 4 wt.%) alloys were investigated to develop new biomedical materials used for dental implant application. The microstructure, residual porosity and the mechanical properties of the sintered Ti12Mo6ZrxFe alloys were investigated by using optical microscopy, X-ray diffraction (XRD), Scanning Electron Microscopy (SEM(, Energy dispersive X-ray (EDX), microhardness and bending stress-strain curves. The results indicated that addition of Zr and a small amount of Fe improves the beta-phase stability and improving the properties of Ti-Mo alloy. In addition, with increasing the sintering temperatures, the microstructure became more homogeneous for beta phase, which decreases in the modulus and strength. The Mechanical alloying allows highly homogeneous composition and particle morphology. Bending strength in EB is much higher than MA techniques. Increasing of compaction pressure during MA technique increases the bending strength and decreases the porosity. Moreover, the Ti12Mo6Zr2Fe alloys exhibited higher bending strength/modulus ratios. (C) 2017 Elsevier B.V. All rights reserved.The authors would like to thank the SME (Electron Microscopy Service) of the Universitat Politecnica de Valencia (UPV) - Spain, the Spanish Ministry of Economy and Competitiveness under the Research Project MAT2014-53764-C3-1-R, and the European Commission due to the FEDER funds.Mohan, P.; Elshalakany, AB.; Osman, T.; Amigó, V.; Mohamed, A. (2017). Effect of Fe content, sintering temperature and powder processing on the microstructure, fracture and mechanical behaviours of Ti-Mo-Zr-Fe alloys. Journal of Alloys and Compounds. 729:1215-1225. https://doi.org/10.1016/j.jallcom.2017.09.255S1215122572

Microstructure and Mechanical Properties of Ti-Mo-Zr-Cr Biomedical Alloys by Powder Metallurgy

[EN] Titanium and its alloys have been widely used as biometals due to their excellent biocompatibility, corrosion resistance and moderate mechanical properties. Ti-15Mo-6Zr-based alloys and a series of Ti-15Mo-6Zr-xCr (x = 1, 2, 3, 4 wt.%) alloys were designed and fabricated by powder metallurgy for the first time to develop novel biomedical materials. The microstructure, internal porosity and mechanical properties of the sintered Ti-15Mo-6Zr and Ti-15Mo-6Zr-xCr alloys were investigated using scanning electronic microscopy (SEM) and bending and compression tests. The experimental results indicated that the microstructure and mechanical properties of these alloys changed as different Cr levels were added. The addition of small Cr levels further increased the β-phase stability, improving the properties of the Ti-15Mo-6Zr-xCr alloy. However, all of the alloys had good ductility, and the Ti-15Mo-6Zr-2Cr alloy had lower bending and compression moduli (31 and 23 GPa, respectively) than the Ti-15Mo-6Zr-based alloys (40 and 36 GPa, respectively). Moreover, the Ti-15Mo-6Zr-2Cr alloys exhibited higher bending and compression strength/modulus ratios, which were as large as 48.4 and 52.2, respectively; these were higher than those of the Ti-15Mo-6Zr-based alloy (41.3 and 33.6, respectively). In the search for a better implant material, β phase Ti-15Mo-6Zr-2Cr, with its low modulus, ductile properties and reasonably high strength, is a promising candidate.The authors thank the Ministry of Economy and Competitiveness for financially supporting the research project MAT2014-53764-C3-1-R and the European Commission through the Erasmus Mundus scholarship program WELCOME. The European Commission via FEDER funds allowed for the purchase of equipment for research and Microscopy Service of the Polytechnic University of Valencia.Elshalakany, AB.; Ali, S.; Amigó Mata, A.; Eessaa, AK.; Mohan, P.; Osman, T.; Amigó, V. (2017). Microstructure and Mechanical Properties of Ti-Mo-Zr-Cr Biomedical Alloys by Powder Metallurgy. Journal of Materials Engineering and Performance. 26(3):1262-1271. doi:10.1007/s11665-017-2531-zS12621271263M. Geetha, A.K. Singh, R. Asokamani, and A.K. Gogia, Ti Based Biomaterials, the Ultimate Choice for Orthopaedic Implants—A Review, Prog. Mater Sci., 2009, 54, p 397–425M. Ahmed, D.G. Savvakin, O.M. Ivasishin, and E.V. Pereloma, The Effect of Ageing on Microstructure and Mechanical Properties of Powder Ti-5Al-5Mo-5V-1Cr-1Fe Alloy, Mater. Sci. Eng., 2014, A605, p 89–97M. Niinomi, Mechanical Biocompatibilities of Titanium Alloys for Biomedical Applications, J. Mech. Behav. Biomed. Mater., 2008, 1(30–4), p 2M.P. Licausi, A. 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Influence of β-phase stability in elemental blended Ti-Mo and Ti-Mo-Zr alloys

This paper investigated the improvement of mechanical properties for one of the most used biomaterials, titanium-based alloy. To improve its mechanical properties, molybdenum was chosen to be added to Ti and Ti-Zr alloys through a mechanical blending process. After homogenization of Ti (12, 15) Mo and Ti (12, 15) Mo-6Zr, the compaction pressure and sintering temperature were varied to create pellets. Characterization has been done using scanning electron microscopy (SEM), X-ray diffraction (XRD), Vickers’s hardness, Archimedes test and ultrasonic method, and 3-point bending test. Micrograph of each pellet revealed the influence of Mo content that plays a prominent role in the variation of microstructure in the alloys Ti-Mo and Ti-Zr-Mo. The porosity and density were also influenced by changing the β-phase. EBSD analysis shows the increase in β-phase with the addition of Zr. The overall results indicated that the percentage of β-phase greatly affects the mechanical properties for the specimens

Microstructure and Mechanical Properties of MWCNTs Reinforced A356 Aluminum Alloys Cast Nanocomposites Fabricated by Using a Combination of Rheocasting and Squeeze Casting Techniques

A356 hypoeutectic aluminum-silicon alloys matrix composites reinforced by different contents of multiwalled carbon nanotubes (MWCNTs) were fabricated using a combination of rheocasting and squeeze casting techniques. A novel approach by adding MWCNTs into A356 aluminum alloy matrix with CNTs has been performed. This method is significant in debundling and preventing flotation of the CNTs within the molten alloy. The microstructures of nanocomposites and the interface between the aluminum alloy matrix and the MWCNTs were examined by using an optical microscopy (OM) and scanning electron microscopy (SEM) equipped with an energy dispersive X-ray analysis (EDX). This method remarkably facilitated a uniform dispersion of nanotubes within A356 aluminum alloy matrix as well as a refinement of grain size. In addition, the effects of weight fraction (0.5, 1.0, 1.5, 2.0, and 2.5 wt%) of the CNT-blended matrix on mechanical properties were evaluated. The results have indicated that a significant improvement in ultimate tensile strength and elongation percentage of nanocomposite occurred at the optimal amount of 1.5 wt% MWCNTs which represents an increase in their values by a ratio of about 50% and 280%, respectively, compared to their corresponding values of monolithic alloy. Hardness of the samples was also significantly increased by the addition of CNTs

Tribological Performance and Rheological Properties of Engine Oil with Graphene Nano-Additives

Nanoparticles dispersed in lubricants are being studied for their ability to reduce friction and wear. This paper examines SAE 5W-30 oil enhanced with dispersed graphene nanoplates for tribological and rheological properties. Graphene nanoplate (GNs) concentration effects on the rheological and tribological properties of 5W-30 base oil (0.03, 0.06, 0.09, 0.12, and 0.15 wt percent) were tested. Under various loads, a four-ball testing model was used to conduct a tribological analysis (200, 400, 600, and 800 N). Kinematic viscosity is calculated, and base oil and nanofluid-added 5W30 lubricant are compared for thermal conductivity and flashpoint. Wear scar and coefficient of friction improved by 15% and 33% with nano-additives. When related to the base oil, the flashpoint, thermal conductivity, kinematic viscosity, and pour point all increased, by 25.4%, 77.4%, 29.9%, and 35.4%, respectively. The addition of GNs improved the properties of 5W30 engine oil