Advanced Materials Research Vols. 503-504

Abstract: TiO₂/(Ag) thin films were prepared by DC magnetron sputtering. The effects of Ag-doping on the microstructure and properties were compared studied by atomic force microscopy (AFM), X-ray diffraction (XRD), UV-Vis spectra and photocatalysis tesing, respectively. The results show that when doped with Ag, the surface of TiO₂ thin film was improved and the growth of anatase phase was promoted. The absoption properties of Ag-doped TiO₂ thin film was enhanced dramatically compared with that of TiO₂ thin film. And the photocatalysis properties of Ag-doped TiO₂ thin film was increased twice as well.

Abstract: In this paper, the influence of different machining methods (including rough turning, finish turning, and longitudinal polishing after finish turning) on rotating bending fatigue properties of TC21 which belonged to a new ultra high strength titanium alloy was studied. The influence of machining methods on surface integrity of TC21 titanium alloy was measured by using surface profile measurement, scanning electron microscopy, metallography microscope, micro-hardness instrument and X-ray diffraction residual stress analyzer. And fatigue fractography of specimens was further investigated. Then the mechanism of fatigue resistance which was affected by machining surface integrity was discussed. The results indicated that the fatigue life of finish turning and longitudinal polishing after finish turning was increased 3.96 times and 17.34 times compared with rough turning, respectively. The machining surface integrity had important influence on fatigue property of TC21 titanium alloy, which caused by the differences of surface roughness and texture as the dominant factors, and then the variation in surface micro-hardness, metallographic microstructure and the surface residual stress were not the main factors on three above-mentioned machining methods. By using longitudinal polishing after finish turning processing method for preparation of TC21 titanium alloy parts could ensure good surface integrity and excellent fatigue performance.

Abstract: The typical chemical reactions of metal were analyzed in this paper, and the two-phase equilibrium line calculated model was obtained. By use of the physical properties database, the design of chemical reactions and the compounds were to be determined. Through the calculating the two-phase point and three-phase point ,the predominance area phase diagram algorithm based on the physical properties database was formed, which has clear physical meaning and accuracy calculation result, and also whose result was consistent with that of the literature.

Abstract: It has been one of the difficulties that high-precision thin hole is machined. The supersonic vibration reaming acoustic system is installed in the lathe. The supersonic wave energy applies to reamer to create pulse power on the cutting process. The separating vibration cutting is achieved to make the pulse force. The tests on reaming surface quality and precision are carried. The quality of surface and accuracy machined by this method is more than that by grinding. The reaming process is stability. The cutting force is greatly reduced. The cutting temperature is at room temperature. The tool life is greatly increased. Surface quality and shape precision is greatly improved. The regulations of the ultrasonic vibration reaming thin hole in hardened steel are also summarized. The test results show that the ultrasonic vibration reaming by reamer is of very superior cutting mechanism. It is efficient cutting methods for high-precision thin-hole machining of hardened materials,

Abstract: In this paper, the bottom pouring vacuum suction casting is used, and the TiAl-based alloy blade with a certain flexivity, the brim thickness 1.5mm, and the blade Falcon with high 8mm, width 10mm, length 27mm was obtained. The structures of this blade are studied. The grain sizes are different from bottom to top, in bottom position, the blade leaves structure have the equiaxed, and the central part have the columnar crystals. The TiAl-based alloy structures have fully lamellar. Comparing with different position structures, the bottom position TiAl based alloy structure have the least lamellar space, is about 0.13μm; the average space of top lamellar structure is about 0.38μm; the central region of the lamellar spacing slightly larger than the bottom area.

Abstract: The ZGMn13Cr2 reinforced by the nano-SiC master alloy is investigated in this paper. The nano-SiC master alloy which comprise nano-SiC powders and other metal powders are prepared, then the nano-SiC master alloy is added into the ZGMn13Cr2 samples under industrial conditions. The morphology and mechanical properties of the samples are studied. The results show that: When the nano-SiC Master Alloy is added into the sample, the microstructure of ZGMn13Cr2 improve significantly and the absorbed energy of the samples increased obviously.

Abstract: A kind of (Fe,Cr)₇C₃particles reinforced iron matrix composite was prepared by metallurgical bonding between Cr wires and gray cast iron at 1200°C with subsequent heat treatment. The obtained composites were comparatively characterized by XRD, SEM and microhardness tests. The results showed that the composites mainly consisted of α-Fe matrix and the reinforcements of particle bundles, which include (Fe,Cr)₇C₃ carbides and γ-Fe. The cross-section of the reinforcements gradually increase with heat treatment time, and the microstructures change from eutectic to hypoeutectic, the morphologies of the reinforcements present chrysanthemum-shaped, granular and intercrystalline eutectics.

Abstract: The lipids from fermented mycelium of G. frondosa were extracted using supercritical flow CO2 and analyzed by GC-MS. There were 24 compounds detected in the lipids and the main compositions were octadecadienoic acid, eicosadienoic acid and hexadecanoic acid, with a little terpenoid compounds of cedrene, caryophyllene, isopropenylcarene, squalene, and some ergosterol. The total fatty acid content of the lipid was 89.18%, in which, the unsaturated fatty acid was 71.09%. The main compositions of saturated fatty acid were hexadecanoic acid and the main compositions of unsaturated fatty acid were linoleic acid and eicosadienoic acid (EDA). The contents of linoleic acid and EDA in the lipid from G. frondosa mycelium were 48.65% and 29.91% respectively.

Abstract: Cast iron was chromized by solid powder method at 1000°C. Micro-morphology and microstructure of chromized alloy layer and cast iron matrix were analyzed, their hardness, elements distribution and corrosion resistance were studied in depth. The analysis results revealed that the chromized carbide-chromium layer grew well on cast iron surface, which was smooth and free from macroscopic defect. Campared with the hardness of original cast iron matrix, the hardness of the chromized alloy layer has been improved by 3.5 times, which was as high as 918.8 HV. And the corrosion resistance of the chromized alloy layer has been greatly improved. The relative corrosion rate of the original cast iron matrix was 2.2 times that of the chromized alloy layer according to their polarization curves.

Abstract: In electrolytes TiO2-based complex ceramic coatings containing Ca and P on titanium alloy were ultimately formed containing zirconia/hydroxyapatite by Micro-arc oxidation process. As well as the biomechanics measure experiment of speciments had been done, and the datas were analysised and researched. In addition, the toughening mechanism of reinforced coating was studied in detail, and consists of the second phase toughening, phase transformation toughening and microcrack toughening.The results show that the zirconia /hydroxyapatite coating has advanced biomechanics propertys compared to the individual hydroxyapatite one.