Showing papers by "Huijun Yu published in 2015"
TL;DR: In this paper, the influence of the electrolyte, process parameters, pretreatment and post-treatment on the coating characteristics (surface micrograph, adhesion strength and biological compatibility etc.) is detailed.
243 citations
TL;DR: In this paper, metal matrix composite (MMC) coatings were fabricated on Ti-6Al-4V titanium alloy by laser cladding and microstructures and wear properties of the different composite coatings are investigated comparatively.
113 citations
TL;DR: In this article, the microstructures and wear resistance of the reinforced composite coatings with and without Y 2 O 3 addition were investigated, and the results showed that the coatings were mainly comprised of γ-Co/Ni, TiN, CoTi, Co Ti 2, NiTi 2, NiTi, TiC, Cr 7 C 3, TiB, Ti 5 Si 3 and TiC 0.3 N 0.7 phases.
86 citations
TL;DR: In this article, Ni-based superalloys with niobium (Nb) or/and yttrium (Y) were prepared by vacuum melting and the oxidation kinetics of these alloys were studied by thermogravimetry at 800 °C for 100 h in static air.
Abstract: Ni-based superalloys with niobium (Nb) or/and yttrium (Y) were prepared by vacuum melting. The oxidation kinetics of these alloys was studied by thermogravimetry at 800 °C for 100 h in static air. Morphology of oxides was studied using SEM, and the composition was analyzed by X-ray diffraction. Energy-dispersive X-ray spectrometer was employed to examine the linear element distribution of the cross section of the oxidation films. Results showed that the oxidation kinetics all followed a parabolic law at different stages. The oxide films were mainly comprised of Cr2O3, NiCr2O4, Al2O3 and TiO2. All the oxide films exhibited layered structure owing to different oxidation stages. With the addition of Nb or Y, the high-temperature oxidation resistance of the superalloy was improved significantly and the surface morphology of the oxidation film was ameliorated. The comprehensive effect of Nb and Y was remarkable in improving the high-temperature oxidation resistance of Ni-based alloys. Copyright © 2014 John Wiley & Sons, Ltd.
31 citations
TL;DR: In this article, high temperature oxidation behaviors of Ni-based superalloys with different contents of Nb addition were investigated by thermogravimetry. And the results showed that irrespective of the composition, all specimens obeyed the parabolic law during different stages.
Abstract: Ni-based superalloys with different contents of Nb addition were fabricated by vacuum melting and casting. High temperature oxidation behaviors of the designed alloys were investigated by thermogravimetry. Microstructure and phase constituent of the oxidation scales were studied using scanning electron microscope and X-ray diffraction (XRD), respectively. Results showed that irrespective of the composition, all specimens obeyed the parabolic law during different stages. The scales on specimens B and C with 2.0 wt.% and 2.5 wt.% Nb addition, respectively, were mainly comprised of Cr2O3 and NiCr2O4. However, specimen A, with no Nb addition showed only NiO in the outer scale. The oxidation scales all exhibited a layered structure. With 2.0 wt.%Nb addition, the superalloy's high temperature oxidation resistance was enhanced by about 25%.
15 citations
TL;DR: In this paper, the effect of Nb or/and Y on hot corrosion resistance was investigated by corrosion kinetics, and the action mechanisms of nb and Y were discussed.
Abstract: The hot corrosion behaviors of new-type Ni–Cr-based superalloys were investigated at elevated temperature. The effect of Nb or/and Y on hot corrosion resistance was investigated by corrosion kinetics. Surface morphology of the corrosion products was observed by SEM and the phase constituents were analyzed by XRD. Results showed that the corrosion scales of the Ni–Cr-based alloys consisted of Cr2O3, Al2O3, TiO2, and NiCr2O4. NiO was only detected in the alloy without Nb and Y. With the addition of Nb or/and Y, the hot corrosion resistance of the alloy was notably improved. The action mechanisms of Nb and Y were discussed in this study.
14 citations