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This work proposes an effective design of bioactive 3D-printed Ti-6Al-4V scaffold with the CaO-MgO-SiO 2 glass-ceramic coating to realize a comparable elastic modulus of bone tissue and boost osteogenic differentiation. The improved elastic modulus and stiffness of Ti alloy were achieved via effectively increasing surface area of Ti alloy to reduce stress shielding effect. A hydrophilic surface and bioactive glass-ceramic coating were conducted via chemical etching and heat-treatment under argon atmosphere to enhance cells attachment and boost cell proliferation and osteogenic differentiation. The expression of osteogenic genes in bioactive CaO-MgO-SiO 2 glass-ceramic was evaluated through ALP, OPN, Runx2, and Col1A1 gene markers to explore the mechanism of superior osteogenic differentiation. Significant increase in OPN expression level confirmed the effect of CaO-MgO-SiO 2 coating for the enhancement of osteogenic bioactivity. This work provides a feasible approach through surface etching and bioactive CaO-MgO-SiO 2 glass-ceramic coating on the Ti alloy surface to enhance bioactivity and osteogenesis. [Display omitted] • A compatible bone tissue of 3D-printed Ti-6Al-4V scaffold with the novel bioactive CaO-MgO-SiO 2 glass-ceramic coating. • A superior surface modification to enhance cells attachment and boost cell proliferation and osteogenic differentiation. • This work provides a feasible approach on the Ti-alloy surface to enhance bioactivity and osteogenesis. [ABSTRACT FROM AUTHOR]

Plasma electrolytic oxidation (PEO) treatment has been performed on AZ91 Mg alloy in a silicate-containing alkaline electrolyte to disclose the relationship between second phase and resultant coating. The morphology and corrosion behavior were characterized for PEO coatings on three different AZ91 substrates with microstructures altered by heat treatment. In the presence of β phase, both the substrate and PEO coating exhibit enhanced corrosion resistance with finer and more evenly distributed β phase precipitates. In the as-cast AZ91, the anodized coating displays chemically and morphologically discontinuity on α and β phase with very coarse and defective regions on two-phase boundaries. In aged AZ91 with nano-sized β phase precipitates, the PEO coating shows no obvious difference on two-phase boundaries and is more homogenous with fewer pores and defects. The residual stress values given by X-ray diffraction (XRD) analysis indicate that PEO coating on aged AZ91 with finest β phase has the smallest stress which might be the reason for its improved corrosion resistance under synergetic effect of corrosive ions and residual stress. Conversely, in the absence of β phase, i.e. after solid solution treatment, the coating is characterized by the most inhomogeneous microstructure and the worst corrosion resistance, presumably owing to the absence of protective aluminum-containing oxides in the coating and more severe localized oxidation behavior adjacent to AlMn phase. Understanding the effect of second phase on PEO coating will enable us to optimize porous oxide structures for improved corrosion resistance by properly altering the substrate microstructure. [ABSTRACT FROM AUTHOR]

• The radii of the nanoscale precipitates are dramatically smaller in the annealed Cu-2Ag-0.14La alloy than in the annealed Cu-2Ag alloy. • The grain size of annealed Cu-2Ag-0.14La alloy is always smaller than that of the annealed Cu-2Ag alloy from 400 °C to 650 °C. • Precipitation strengthening of nanoscale precipitates in the matrix and grain-boundary strengthening during grain refinement substantially improve the yield strength of the Cu-2Ag-0.14La alloy. [Display omitted] A new Cu–2Ag–0.14La alloy is developed to enhance the mechanical property and electrical conductivity with inducement of Ag-rich primary phases and finer nanoscale Ag precipitates. The microstructural evolution and mechanical properties of Cu–2Ag–0.14La and Cu–2Ag alloys obtained by drawing and annealing were then summarized and analyzed. The results indicate that both the yielding and ultimate tensile strengths of annealed Cu–2Ag-0.14La alloy were reinforced after La modification. The average grain sizes of two alloys increase during annealing, but the size ratio (R Cu-2Ag-0.14La /R Cu-2Ag) dramatically varies with rising the heat temperature, evolving from 70.48% at 400 °C to 43.78% at 650 °C. Meanwhile, it is found that the refined grains sizes in Cu-2Ag-0.14La alloy are closely related to the nano-scale precipitates (~450 nm), which hinder the formation of subgrain boundaries at 400 °C, and impose a stronger pinning effect on boundary migration of recrystallized grains during annealing (≥ 450 °C). Consequently, higher hardness and electrical conductivity are contributed by grain refinement and dispersion strengthening of the nanosized phases. [ABSTRACT FROM AUTHOR]

The cyclic stability of hydrogen absorption and desorption is an important indicator of hydrogen storage alloy. The decay mechanism was roundly investigated by controlling the depth of dehydrogenation (DOD) of the V 40 Ti 25.5 Cr 26.5 Fe 8 alloy during the process of hydrogen ab/desorption cycles. The V 40 Ti 25.5 Cr 26.5 Fe 8 alloy exhibits the hydrogen desorption capacity of 2.36 wt% at 323 K in the first cycle. After 30 cycles, the decay rate of the hydrogen desorption capacity is only 4.37 % at 40 % DOD, but rises to 8.74 % at 100 % DOD. The hydrogen desorption capacity (C), plateau pressure (P) and micro-strains (S) all show an "acceleration followed by slowing" exponential variation trend with the increase of cycle number (x). Additionally, any two of C , P and S show linear correlation. It is considered that the micro-strains in the crystal lattice is the main factor for the decay of the hydrogen desorption capacity and the plateau pressure. On the premise of ensuring the valid hydrogen storage capacity to meet the requirements of the application, properly reducing DOD per cycle can effectively reduce the micro-strains accumulation and cell volume expansion, thus improving the cyclic stability of the alloy. Moreover, the application of this alloy in a fuel cell bicycle was investigated, and the total range and mileage per unit weight of the alloy are up to 100.8 km and 15.7 km/kg, respectively. Compared with the lead-acid battery, lithium-ion battery and LaNi 5 -based hydrogen fuel cell, the V-Ti-Cr-Fe-based fuel cell shows significant advantages. ● A bran-new method was proposed to slow down the decay of the dehydrogenation capacity of the V 40 Ti 25.5 Cr 26.5 Fe 8 alloy. ● The alloy decay rate of the dehydrogenation capacity is only 4.37% after 30 cycles at 40% DOD, only half that at 100% DOD. ● Six functions were proposed to explain the influences of the micro-strains in the lattice. ● This alloy fuel cell shows significant advantages compared with other batteries through application in a fuel cell bicycle. [ABSTRACT FROM AUTHOR]