Advanced Materials Research Vol. 842

Abstract: Springback is one of the major problems of high strength steel.Based on the NUMISHEET’96 S_Rail standard examination questions,using the characteristics of the servo press 200T,the blank holder force,different pressure holding time and the holding times of advanced high strength steel DP280-440, DP340-590, DP400-780 are studied. By changing one of the three impact factors ,three group experiments are carried out.The experimental results show that the springback can change evidently with the increasing of the blank holder force and the holding times,but the holding time has little influence on the springback.What’s more,the springback angle of DP400-780 is the biggest ,proving the higher the yield stress,the bigger the springback angle.Therefore, in the stamping of advanced high strength steel, increasing the blank holder force and holding times are effective methods to solve the springback.

Abstract: Three-dimensional graphene foam (GF) is synthesized by chemical vapor deposition (CVD) at ~1000°C under ambient pressure. Then it is characterized by scanning electron microscopy (SEM) and laser Raman spectroscopy, the results indicate that GF has changed the surface morphology of Ni foam, and ~ 98% of the GF are fewlayer. At last, the surface wettability of GF is investigated, which shows that it is hydrophobic. The special three-dimensional structure and excellent properties of GF make it a candidate for a range of applications.

Abstract: To produce Nd, of Yb: YAG laser crystal by use of medium frequency induction heating Czochralski method.Taking advantage of the XRD, absorption spectra and fluorescence spectra on the crystal of the phase structure of and spectral to analyze the performance of structureshows that: Nd, Yb: YAG crystals belong to the cubic crystal system with the lattice parameters a = 1.2021 nm. There is a strong absorption in the 808nm but under the common temperature Nd, Yb: YAG crystal fluorescence spectra of the strongest fluorescence emission peak at 1030nm, attributable to the Yb^{3 +} ion ²F_5/2²F_7/2 level transition

Abstract: A new type of polyaspartic acid ester (PAE) was synthesized by double alkyl malay acid ester and bis-(p-aminocyclohexy) methane (PACM) via a Michael addition reaction. The Fourier transform infrared spectrometer shows the reaction can take place in room temperature. The dynamics of the reaction were investigated by mercaptan-iodine titration analysis method at 57°C and 67°C. The results showed the reaction order between double alkyl malay acid ester and bis-(p-aminocyclohexy) methane (PACM) was three. The solvent free polyaspartic polyurea coating was developed with the synthesized resin and the properties were tested with good results.

Abstract: TiAlSiN coatings with Ti or Cr interlayers were deposited on high-speed steel using magnetron sputtering methods. The structure, crystal morphology and mechanical properties were investigated systematically. The results show that (200) is the dominant preferred orientation in Ti/TiAlSiN coating, while (111) become the predominant orientation of the deposited Cr/TiAlSiN coating, which is related to the surface energy. Due to the changes of the coating growth style, the Cr/TiAlSiN coating shows columnar crystals morphology. The Ti/TiAlSiN coating performs better adhesion and H/E ratio, which is proved to have better wear resistance. But the specimens with Cr interlayer have better hardness and elastic modulus, which is due to the growth style of the crystals.

Abstract: In this study, low temperature plasma carburizing of austenitic stainless steels has been studied, with the aim to improve the hardness and wear resistance of austenite layers. Austenitic stainless steels were plasma carburized at 450°C, using C3H8 as carbon carrier gas. Depth profiles of hardness, hardness distribution and the friction coefficient of carburized layer were measured. The results show that carburized layers range from 10 to 20μm, causing the improvement of the hardness and wear resistance of the surface of austenitic stainless steels.

Abstract: In order to improve corrosion resistance of friction stir welds of Mg alloy, Al coatings were fabricated by cold spraying on Mg alloy substrate. The microstructure and microhardness of friction stir weld and coatings are investigated with optical microscope and hardness machine. The results indicate that Al coatings present a smooth surface, low porosity and well bonding with substrate. The grains size of friction stir welds increase as substrate speed decrease or powder feeder wheel speed increase, while the microhardness decrease since residual stress in coatings and substrate reduces. The experimental results demonstrate that Al coatings fabricated by cold spraying can provide potential protection for as cast friction stir welds of AZ31 Mg alloy.

Abstract: The paper describes research into the production of ceramic powder. Ceramic powder or ceramic granulate is the product that arises in spray drying emulsion. In our case was investigated granules - Silicon carbide (SiC). Silicon carbide is one of the most used materials in engineering technology. The essence of the research was to create a mathematical model of the drying process and identify the parameters influencing drying. Mathematical model was used to create balance equations, from which it was expressed parameter - mensural granulate moisture u₂. Endpoint was the absolute humidity of dry gas to exit the furnace Y₂. Based on the measured and calculated values was created graph absolute humidity drying gas furnace outputs for mensural material moisture output furnace.

Abstract: In order to know the coating effect and application of color ink-jet paper, the coating formula and printing quality of ink-jet paper were deeply studied. First of all, the coating liquid was prepared by dispersing and mixing the nanometer pigment, the adhesive and the other additives. Then the properties of ink-jet paper were tested and their surface profiles were characterized and evaluated with scanning electron microscope. Finally, the coating paper samples and the base papers were all printed with color ink-jet printer and measured with a spectrodensitometer. The study result showed that it can gain well coating and printing quality when the ratio of SiO₂ and TiO₂ is 3:1 and the content of PVA adhesive is 50%, especially paper whiteness is obviously higher than that before the coating.

Abstract: In this work, TiC-10Ni coating was synthesized on copper substrate by electro-thermal explosion directional spraying (EEUSS) method at the discharge voltage of 26kV. Electrical characteristics of the explosion were obtained. The foil was overheated in less 26 microseconds. The total electric energy supplied to the foil was 12.7 times the theoretical amount needed to melt the foil. Phase structure and microstructure of the coating were studied by means of X-ray diffraction (XRD) and scanning electron microscope (SEM). The XRD from the coating surface consists of TiC and the solid solution of Ni, as well as the residual C. The TiC-10Ni coating, which exhibits no pores or cracks, consists of an irregular spheroidal TiC phase embedded in a nearly continuous binder. TiC particles are uniformly distributed and the size of the TiC particle of the coating is less than 1.0 μm because of the solute trapping effect.