Applied Mechanics and Materials Vol. 189

Abstract: Analyzed the melting process of iron base which contacted tightly with boron slag, established the boriding melting dynamical model of iron base and calculated the melting rate of pure iron. The melting rate of pure iron is not only decided by heat transfer rate, but also related to the mass transfer rate of boron. With the resolving of the model, we can know that the melting rate of pure iron is 3.41mm/min, and melting time is 15 min. When the speed of heating is high, the melting rate is mainly decided by diffusion.

Abstract: A lab radio frequency (RF) magnetron sputter coating system was used to deposit the nanoscale copper (Cu) films onto the surface of polyester plain fabric at room temperature. In this study,the polyester fabrics were treated under different duration with low temperature plasma.The effect of oxygen plasma pretreatment on surface morphologies,antistatic properties,mechanical properties of the copper-coated polyester fabrics is investigated. The surface morphology of modified polyester fabrics was characterized by atomic force microscopy (AFM).The AFM observations revealled the obvious corrasion was formed on the fiber surface,the sputtered copper particles were hard to cluster and uniformly distributed on the fiber surface with longer duration of plasma treatment.The antistatic properties of the copper-coated polyester fabrics was greatly improved after the oxygen plasma treatment.The hydrophobic behavior of the coated samples was also significantly improved .

Abstract: In this paper, with the combination of powder metallurgy and hot pressing method, the nano-graphite Al-Mg composite material was made. This method succeeds in solving the difficulty that graphite particle directly melted with Al-Mg melt, which investigates the amount of nano-graphite’s impact on the abrasion resistance of Al-Mg composite material. The result shows that nano-graphite particle easily to scattered in the matrix when the nano-graphite particle amounts to 1﹪ which can decrease the friction coefficient of composite material. But the material of wear extent increases accordingly along with the increase of the content of nano-graphite.

Abstract: T-400 is an elastic fiber developed by Dupont. It was commended as one of the best developing prospect chemical fiber in the 21 century. In this paper, the mechanical property of spun silk/T-400 interlaced fabric with different weave was studied. The drawing, peaking, bending and abrasive characteristics of the spun silk/T-400 interlaced fabric with different fabric weave were tested and analyzed. The drawn broken strength and elongation at warping and weft orientation increased with the average float increased. The peaking broken strength is bigger if the average float is longer. The bending length and rigidity increased as the average float of the fabric increased. That can make the abrasive resistance characteristic of the fabric increase. And the correlative curve was pictured and the correlative formula was built.

Abstract: For finding the relation between Martens hardness and Vickers hardness, Rockwell hardness, tensile strength, yield strength, research are done on carbon alloy steel by experiment, linear regression analysis and derivation of equation .Martens hardness, Vickers hardness and Rockwell hardness of 30 samples which contains 3 material and 10 hardness levels are tested by ZHU 2.5 hardness tester. On the basis of 180 groups of data obtained and analyzed from instrumented indentation experiments, mathematic model between Martens hardness and Vickers hardness is established, by linear regression analysis. And mathematic model between Martens hardness and Rockwell hardness, tensile strength, yield strength is established on that basis. By means of comparing the value calculated by the mathematic model and obtained from tensile test using Electronic universal testing machine, the accuracy of the mathematic model is verified. The result show that the relative error of the four mathematics models which established in this test is below 5%, and the four mathematics models can be applied to the practical engineering application.

Abstract: Graphite nanosheets were prepared by sonicating expanded graphite (EG) in a liquid medium. The products were characterized by scanning electron microscope (SEM), and its anti-friction effect used as additive of base oil was investigated. The influencing factors of its anti-friction effect, the weight ratio of graphite nanosheets to base oil, the sonicating medium and sonicating time, were studied and optimized. The results show that under the optimum conditions the graphite nanosheets exhibit an excellent anti-friction effect.

Abstract: Graphite encapsulated nickel nanoparticles were prepared by ball-milling and subsequent annealing a mixture of expanded graphite and nickel powders. The products were characterized by transmission electron microscope (TEM), and their tribological behavior used as lubricating additive was investigated by using a high-temperature tribo-tester. The morphology of the worn tribo-surfaces was observed by scanning electron microscope (SEM). The results show that as-prepared graphite encapsulated nickel nanoparticles with a size range of 10-150 nm have a marked anti-friction and wear resistance effect, and the larger the applied load, the lower the friction coefficient and the wear severity.

Abstract: Fatigue properties are investigated experimentally on grade B steel casted by the resin sand technology in this paper, which aims to study bolsters and side frames of Chinese railway freight cars. To begin with, cracked and non-cracked samples were tested by the group method respectively, and then the two obtained sets of experimental data were separately fitted through the three-parameter model with the conventional method. The influence of dispersion and the sample size on probabilistic evaluation was taken into consideration in terms of the cracked samples, and P (survival probability) -S -N curves as well as confidence limits were estimated. At the same time, by comparing the cracked samples’ median S-N curve with that of the non-cracked ones, we can know that this kind of cracks lower the fatigue strength of grade B steel. At last, the fatigue test that simulated real load conditions indicates that fatigue properties of bolsters and side frames by the resin sand process can meet the work demand in the future.

Abstract: The structural and electronic properties of alkannin and its derivatives and their radicals were investigated at density functional level. It turned out that the presence of the dihydroxy functionality increases the radical stability through hydrogen bond formation. The hydrogen atom transfer for alkannin derivatives is difficult to occur compared with zero compound phenol. However, alkannin derivatives appear to be good candidates for the one-electron-transfer, particularly for alkannin derivatives with –OCOCH=CH(CH3)2 and –OCOCH2CH(CH3)2 groups. It suggests that 1–7 are expected to be the promising candidates for radical scavenging activity compounds because The ionization potential (IP) values of 1–7 are lower than that of the zero compound phenol.

Abstract: Through a new laser welder welding parameters to optimize the welding of high strength steel, thereby contributing to acid-rolling unit efficient and reliable production and energy save. In order to ensure the welding quality, every few volumes, and will cut the crescent do cupping experimental results to determine whether you need to re-welding, to prevent acid rolled off with production efficiency.