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The study presents the results of the influence of high-energy ball-milling time on the structure of the new β-type Ti–Ta–Nb–Zr alloys for biomedical applications. Initial elemental powders were mechanically alloyed in a planetary high-energy ball mill at different milling times (from 10 to 90 h). Observation of the powder morphology after various stages of milling leads to the conclusion that with the increase of the milling time the size of the powder particles as well as the degree of aggregation change. Clear tendency of crystalline size reduction at every stage of the grinding process is clearly observed. The X-ray diffraction results confirmed the formation of βphase during high-energy ball milling of the precursor mixture of Ti, Ta, Nb, and Zr. The Rietveld refinement method has shown that both the production method and the atomic radii of the elements used in the mechanical synthesis have influence on the structure. Furthermore, it was found that a broadening of the diffraction peaks with increase of the milling time results from an increase in the crystallites dispersion and an enlargement in the lattice distortion. The results indicate that this technique is a powerful and high productive process for preparing new β-titanium alloys with nanocrystalline structure and appropriate morphology.

The paper concerns the determination of the role of the γ-phase particles on the microstructure and properties of Co-Ni-Ga alloys. The studies cover the alloys of chemical composition which show two types of microstructure: single phase martensite BCT( Body Centred Tetragonal) lattice with c/a > 1(a), BCT + γ(b). The particle analysis was performed to determine the amount of the γ-phase in the studied alloys. The compression test on prism samples proved that the increase of the γ-phase volume fraction significantly improves the strength and plasticity of the alloys. Thus the presence of the γ-phase precipitates cause the decrease of the brittleness observed in the single phase martensitic alloys. TEM observations were performed for specimens before and after deformation to reveal the mechanism of the γ-phase deformation.

In this work, we describe surface modifications to a Ti6Al7Nb alloy resulting from plasma electrolytic oxidation (PEO) in two different solutions: one containing 0.1 mol/dm3Ca (H2PO2)2and 100 g/dm3TCP (tricalcium phosphate) and another containing 0.1 mol/dm3Ca(H2PO2)2, 25 g/dm3TCP and 1 g/dm3NH4F. As a result of the PEO process, a porous oxide layer containing incorporated calcium and phosphorous compounds was formed on the Ti6Al7Nb alloy surface. The morphology and chemical composition of the Ti6Al7Nb alloy samples were investigated using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy(EDX) and X-ray diffraction (TL-XRD). The contact angle and roughness of the oxide layer were measured. The anodized samples exhibited a higher surface roughness than the non-modified Ti6Al7Nb alloy. Bioactivity investigations using an SBF solution confirmed the formation of apatite on the anodized surfaces. Additionally, the modified surface of the titanium alloy exhibited a higher corrosion resistance than as-ground examples due to the formation of a thin oxide layer on the surface.

In this work, we describe surface modifications to a Ti6Al7Nb alloy resulting from plasma electrolytic oxidation (PEO) in two different solutions: one containing 0.1mol/dm3Ca(H2PO2)2and 100g/dm3TCP (tricalcium phosphate) and another containing 0.1mol/dm3Ca(H2PO2)2, 25g/dm3TCP and 1g/dm3NH4F. As a result of the PEO process, a porous oxide layer containing incorporated calcium and phosphorous compounds was formed on the Ti6Al7Nb alloy surface. The morphology and chemical composition of the Ti6Al7Nb alloy samples were investigated using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (TL-XRD). The contact angle and roughness of the oxide layer were measured. The anodized samples exhibited a higher surface roughness than the non-modified Ti6Al7Nb alloy. Bioactivity investigations using an SBF solution confirmed the formation of apatite on the anodized surfaces. Additionally, the modified surface of the titanium alloy exhibited a higher corrosion resistance than as-ground examples due to the formation of a thin oxide layer on the surface.

The paper concerns the determination of the role of the ?-phase particles on the microstructure and properties of Co-Ni-Ga alloys. The studies cover the alloys of chemical composition which show two types of microstructure: single phase martensite BCT( Body Centred Tetragonal) lattice with c/a > 1(a), BCT + ?(b). The particle analysis was performed to determine the amount of the ?-phase in the studied alloys. The compression test on prism samples proved that the increase of the ?-phase volume fraction significantly improves the strength and plasticity of the alloys. Thus the presence of the ?-phase precipitates cause the decrease of the brittleness observed in the single phase martensitic alloys. TEM observations were performed for specimens before and after deformation to reveal the mechanism of the ?-phase deformation.

Abstract.: The paper concerns the determination of the role of the γ-phase particles on the microstructure and properties of Co-Ni-Ga alloys. The studies cover the alloys of chemical composition which show two types of microstructure: single phase martensite BCT( Body Centred Tetragonal) lattice with c/a > 1(a), BCT + γ(b). The particle analysis was performed to determine the amount of the γ-phase in the studied alloys. The compression test on prism samples proved that the increase of the γ-phase volume fraction significantly improves the strength and plasticity of the alloys. Thus the presence of the γ-phase precipitates cause the decrease of the brittleness observed in the single phase martensitic alloys. TEM observations were performed for specimens before and after deformation to reveal the mechanism of the γ-phase deformation.

The studied composite powder of high corrosion resistance was prepared using the Self-propagating High-temperature Synthesis (SHS) process. The as-prepared material was crushed and was subjected to a milling process by high-energy attritory mill for two and ten hours. The powder morphology was analysed through the Scanning Electron Microscopy (SEM) method. The structure investigations were performed using the SEM and XRD methods. The presence of Cr7C3, FeCr and FeO phases, besides the most desired FeAl(Cr), Cr3C2 and TiC ones, was noted. It was found that the FeAl(Cr) phase is of the ordered B2-type structure and the ordering degree diminishes with the increase of milling time. The crystallite size of this phase, both in the as-prepared state and after the milling process, is in the nanoscale. The crystallite size of the FeO phase diminishes to 75 nm in the sample ground for 10 h, whereas those of the other phases are above 100 nm for the as-prepared and ground samples.