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This work discusses microstructure evolution during ball milling and hot pressing of Ti-xZr-10Si-5B (x = 2 and 5 at. %) and Ti-xZr-20Si-10B (x = 5, 7, 10, 15 and 20 at. %) powder mixtures. Mechanical alloying was carried out in a ball mill using stainless steel balls and vials, 300 rpm and a ball-to-powder ratio of 10:1. Powders milled for 600 min were then hot-pressed (25 MPa) under vacuum at 1100 • C for 60 min. As-milled and hot-pressed samples were evaluated by X-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and energy dispersive spectrometry (EDS). Peaks of Si and Zr disappeared in powders milled for 60 and 180 min, respectively, while the lattice parameters and cell volume of α-Ti were varied during ball milling up to 300 min indicating that supersaturated solid solutions were achieved. Ti 6 Si 2 B dissolving up to 10 at. % Zr was found in microstructure of hot-pressed Ti-xZr-10Si-5B (x = 2 and 5 at. %) and Ti-xZr-20Si-10B (x = 2, 5, 7 and 10 at. %) alloys. The amount of TiB and Ti 5 Si 3 was preferentially increased whereas the Ti 3 Si formed in microstructure of the hot-pressed Ti-15Zr-20Si-5B and Ti-20Zr-20Si-10B alloys.

In this work, CoCrMo-base alloys specimens were produced by additive manufacturing using selective laser melting (SLM) as well as CAD/CAM milling. For SLM specimens, spherical particles were laser processed at 1320°C under argon atmosphere and submitted to thermal stress relieving at 750°C-45min. Specimens from CoCrMo blocks were milled by CAD/CAM machining and sintered at 1300°C-60min. The materials from both techniques were characterized by relative density, dilatometry, SEM/BSE, OM and XRD analysis. The mechanical properties were determined by Vickers hardness and tensile tests. The specimens from both techniques exhibited single phase γCo (FCC) and CTE of 14 x10 -6 °C-1 . Relative density of 95.4%/ 85.6%, hardness values near 400HV/ 350HV and UTS of 905MPa/ 780MPa were measured for SLM and CAD/CAM specimens, respectively. Higher relative density is the main factor for increased mechanical properties of SLM specimens. On the other hand, both SLM and CAD/CAM specimens present properties in accordance with ISO-22674 recommendations, compatible with dental applications such as bridges containing four or more elements as well as fully dense pontics.

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Magnesium is an important base material for non-permanent implants, even though its corrosion rate in the human body is usually elevated for most applications. In order to reduce that rate, polymer coatings can be a better option than heavy-metal containing Mg alloys. In this work, random copolymers of PMMA and PMAA were synthesized and used for coating pure Mg by simply immersing Mg coupons into a diluted copolymer solution. It has been shown by SEM analysis and quantitative adsorption analysis that the copolymers have adsorbed onto the Mg surface. All the coated materials presented a lower corrosion rate than the uncoated Mg, reaching close to 100% reduction for most of the copolymer up to 6 hours of testing. The copolymers with 5, 8 and 13% of PMAA in their composition showed the best performances as corrosion controllers.

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The effects of the Zn content on the mechanical and corrosion properties of MgZnMnCa alloys were investigated. The results revealed that with increasing Zn content up to 4 wt.%, the Mg-4Zn-0.2Mn-0.2Ca (wt.%) alloy after solution treatment at 400°C for 24 h (ZM40-S) exhibited a volume fraction of 1.56 ± 0.05 (vol.%) of secondary phases with an average grain size of 83.6 ± 1.6 µm. This alloy in the at-cast condition exhibited indentation hardness (Hit) of 657.1 ± 17.8 MPa, which increased to 723.5 ± 29.8 MPa after solution treatments. In addition, the alloy also exhibited a Vickers hardness value of 66.8 ± 2.7 HV and an elastic modulus of 33.8 ± 0.6 GPa, close to the values for human bone. Further, the corrosion properties of this alloy were analyzed: it exhibited a cathodic polarization curve attributed to a hydrogen evolution reaction and an anodic curve corresponding to a passivation tendency, indicating the formation of an oxide layer at the surface; further, its corrosion rate was 0.23 mm/year.