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This study aims to achieve in situ-formed pure Ti and Ti6Al4V coatings on 316L stainless steel through hot pressing and examine their wear and corrosion properties thoroughly in two simulated body fluids: physiological serum (0.9% NaCl) and Hanks' solution. The sintering and diffusion bonding process was conducted at 1050 °C under a uniaxial pressure of 40 MPa for 30 min in a vacuum environment of 10−4 mbar. Following sintering, in situ-formed pure Ti and Ti6Al4V coatings, approximately 1000 µm thick, were produced on 316L substrates approximately 3000 µm in thickness. The mean hardness of 316L substrates, pure Ti, and Ti6Al4V coatings are around 165 HV, 170 HV, and 420 HV, respectively. The interface of the stainless steel substrate and the pure Ti and Ti6Al4V coatings exhibited no microstructural defects, while the interface exhibited significantly higher hardness values (ranging from 600 to 700 HV). The coatings improved corrosion resistance in both electrolytes compared to the 316L substrate. Wet wear tests revealed reduced friction coefficients in 0.9% NaCl relative to Hanks' solution, highlighting the chemical interactions between the material surface and the electrolyte type and the significance of tribocorrosion in biocoatings. [ABSTRACT FROM AUTHOR]

The work deals with the technology of microplasma spraying of biocompatible coatings from Zr--Nb alloy and their properties. On the surface of a porous Zr--Nb coating with the most developed surface microrelief, the presence of both open macropores of up to 300 µm in size and micropores of up to 10 µm in size was revealed. The X-ray phase analysis of the formed Zr--Nb coatings showed the presence of phases of a-solid solution of Zr, oxide (ZrO2), nitride (ZrN) and carbide (ZrNbC2). The corrosion resistance of a microplasma Zr--Nb coating and Ti6Al4V alloy in a solution of 0.9 % NaCl, which simulates the environment of the human body, was determined. It is assumed that Zr-Nb alloy coatings produced by microplasma spraying on the surfaces of existing Ti6Al4V alloy endoprostheses will allow for the future improvement in corrosion resistance and osseointegration between the bone and the implant. [ABSTRACT FROM AUTHOR]

For the first time, the present study investigates the corrosion, surface, and subsurface properties of a shot-peened Ti6Al4V powder metallurgical alloy produced via pressure-assisted sintering. Shot peening yielded a fine-grained microstructure beneath the surface down to 100 microns, showing that it caused severe plastic deformation. XRD analysis revealed that the sizes of the crystallites in unpeened and shot-peened Ti6Al4V alloy samples were 48.59 nm and 27.26 nm, respectively, indicating a substantial reduction in crystallite size with shot peening. Cross-sectional hardness maps of shot-peened samples showed a work-hardened surface layer, indicating a ~17% increase in near-surface hardness relative to unpeened samples. Three-dimensional surface topographies showed that shot peening yielded uniform peaks and valleys, with a maximum peak height of 4.83 μm and depth of 6.56 μm. With shot peening, the corrosion potential shifted from −0.386 V to −0.175 V, showing that the passive layer developed faster and was more stable than the unpeened sample, improving corrosion resistance. As determined via XRD analysis, the increased grain refinement (i.e., the number of grain boundaries) and the subsequent accumulation of TiO2 and Al5Ti3V2 compounds through shot peening also suggested the effective formation of a protective passive layer. As demonstrated via electrochemical impedance spectroscopy, the formation of this passive film improved the corrosion resistance of the alloy. The findings will likely advance surface engineering and corrosion research, enabling safer and more productive shot peening in corrosion-critical applications. [ABSTRACT FROM AUTHOR]

Although magnesium is one of the materials with the lowest density, its application is limited amongst other commercial materials due to insufficient strength. Generally, the strength of magnesium can be increased by introducing the Mg17Al12 phase into the structure with the addition of aluminum. In this study, as a different approach, Mg17Al12 particles were added to pure magnesium to form a composite structure. For this purpose, Mg composites with different Mg17Al12 contents were fabricated by powder metallurgy methods. Pure Mg and Mg17Al12 particles were mixed in a vacuum ball milling equipment for 1 h using zirconia balls to obtain the Mg metal matrix composite with homogeneously distributed intermetallic reinforcements. While for pure Mg powders, the sintering temperature was selected as 600°C, for Mg + Mg17Al12 mixtures, it was 420°C due to the eutectic transformation between Mg and Al. The sintering time and pressure of the Mg-based mixtures were held constant for 30 min and 50 MPa, respectively. All sintering processes were carried out under a 10–2 Pa vacuum atmosphere. Microstructural characterization was performed using optical microscopy and scanning electron microscopy. The hardness and wear properties of the composites produced have also been studied. The hardness and wear resistance of composites increased significantly as the Mg17Al12 particle content increased. Although the particle-enhanced composite density increased from 1.72 to 1.92 g/cm3, a 2.4-fold increase in hardness and a two-fold increase in wear resistance was observed. This magnesium composite produced with a new design could be used in many different areas. [ABSTRACT FROM AUTHOR]

Metallic or ceramic micro/nanoporous materials have attracted particular attention due to some interesting structural and functional properties. There exist a variety of methods for producing porous materials by which optimized features can be reached. Spark plasma sintering (SPS) is one of these new-emerging approaches. This technique is often combined with conventional technologies and produce a variety of porous structures with tailorable microstructure and physicomechanical properties. This review addresses SPS and obtainable porous materials with nanoscale and microscale microstructural features. The processing methods, microstructural phenomena, and physicomechanical properties of these materials are discussed in some details, along with the likely future directions required for this novel field. [ABSTRACT FROM AUTHOR]

In this study, the mechanical, antibacterial properties and cell toxicity response of Ti-5Al2.5Fe alloy with different copper contents were investigated. The alloys were prepared by high-energy ball milling using elemental Ti, Al, Fe, and Cu powders and consolidated by a uniaxial vacuum hot press. Staphylococcus aureus strain ATCC 29213 and Escherichia coli strain ATCC 25922 were used to determine the antibacterial properties of the sintered alloys. The in vitro cytotoxicity of the samples was evaluated with HeLa (ATTC, CCL-2) cells using thiazolyl blue tetrazolium bromide. The mechanical behavior of the samples was determined as a function of hardness and bending tests and analyzed by scanning electron microscopy, energy dispersive x-ray spectroscopy, optical microscopy and x-ray diffraction (XRD). The results showed that the Cu content significantly improved the antibacterial properties. Cu addition prevented the formation of E. coli and S. aureus colonies on the surface of the samples. All samples exhibited very good cell biocompatibility. The alloys with different copper contents showed different mechanical properties, and the results were correlated by microstructural and XRD analyses in detail. Our results showed that Cu has a great effect on the Ti5Al2.5Fe alloy and the alloy is suitable for biomedical applications with enhanced antibacterial activity.