Advanced Materials Research Vols. 750-752

Abstract: The effects of surfactants, such as sodium oleate soap, triethanolamine oleate, MOA, OP-4, had been studied for the dispersion of molybdenum disulfide (MoS₂) in aqueous solution. And the lubricating property of the water dispersion system had been observed by four-ball tester. The results show that sodium oleate soap, MOA and OP-4 have the excellent composite effect for the dispersion of MoS₂ aqueous solution, and having a best ratio (wt%) for sodium oleate soap: MOA: OP-4 = 1: 1.8: 2.

Abstract: The electrochemical behaviors of X80 steel under different charging current in an acidic soil solution were investigated by open circuit potential, potentiodynamic scan and electrochemical impedance spectroscopy. Results show that cathodic charging promotes the formation of corrosion product on the electrode surface, accordingly, the OCP changes slightly. The hydrogen ions on electrode surface are exhausted during the charging process, therefore the cathodic reaction is restrained meanwhile the anodic process iron dissolution increases. EIS result shows that the corrosion rate under OCP was inhibited by cathodic charging. However, the anodic process was enhanced by charging under-0.4 V_SCE.

Abstract: Metal rubber is a kind of pure metal structure of the porous material. The paper, starting from the internal structure of metal rubber, based on the theory of porous, based on dry friction nonlinear theory, establishing the unit model of porous metal rubber material, for the development of product design and application of the metal rubber material to provide a theoretical basis.

Abstract: The worn Cu-based friction disks were repaired and remanufactured by the spark plasma sintering (SPS) technology. The morphology and component of the repaired friction disk were analysed by SEM and EDS. The mechanical properties were characterized by microhardnessmeter and friction tester. The results indicated that the microstructure of the repaired areas combined closely with the worn areas and the components were well-distributed. The friction coefficient of the repaired materials is close to the unrepaired, but the hardness declined slightly.

Abstract: MgAlON is a new type of refractory material. This article summarized the advantages and disadvantages of the preparative technique through different methods including aluminothermic reduction, carbothermal reduction-nitridation, reaction sintering, spark plasma sintering and so on. The future development was also discussed.

Abstract: This paper studies the damage process induced by dewetting microcracks in composite solid propellant. A nonlinear viscoelastic constitutive model for composite soild propellant is presented. The damage variable D is derived from the microcrack system and is function of microcrack size density. The damage evolution equation is determinded by the extending of microcrack. Form the proposed model of microrack evolution process, an explicit form of damage evolution equation which is a function of stress field is given. The cracking event N and the new crack surface area damage ΔA formed by microcrack extension are defined. Material constants are determinded by acoustic emission tests. The rationality of our model has been confirmed by tension tests.

Abstract: In this presented work, a coupled thermo-mechanical model is employed to analyze the thermo-mechanical behavior of ceramic functionally graded materials (FGMs) and the crack formation and propagation process of ceramic coating was simulated step in step and step by step using the RFPA (Realistic Failure Process Analysis) ^2D-Thermo code. The thermal shock fracture behavior is discussed based on the basis of the simulated crack morphology and elucidated the mechanism of crack deformation and crack propagation. The state change from compression to tension whose magnitude is large enough to exceed the tension strength of ceramic causes the vertical crack. The numerical results agreed well with the experimental results in the previous literature.

Abstract: The radioactive decay of Pu produces He atom, which may form cluster with vacancies or accumulate into He bubble, thus resulting in physical, chemical and mechanical changes. In this paper first principle evaluations of Pu lattice defected with mono-vacancy (or di-vacancy) and He atoms have been performed using the generalized gradient approximation (GGA) of the density functional theory and Perdew-Burke-Ernzerhof (PBE) exchange-correlation functional. The simulation results indicate that the density of states (DOSs) of Pu lattices seem stable when He/V (V represents vacancy) ratio is between 2:1-3:1, the partial DOSs of s, d and f states shift in the orientation of positive X axis, while f state peaks disappear around the Fermi level. Total energy per Pu atom in Pu lattice with mono-vacancy (or di-vacancy) and He atoms relative to total energy per Pu atom in perfect fcc Pu lattice nearly remains constant (about 8.18a.u.).

Abstract: Based on the thermo elasticity theory, the stress of femur prosthesis system was analyzed using finite element method. An evaluation for the selection of prosthetic material was presented after discussing the thermo physical property of material which had an effect on the stress of femur prosthesis system. The results indicate that the interface failure is the primary failure form of the femoral prosthesis system and the interface failure is accelerated for the reason of the thermal effect. So the prosthesis with low coefficient of thermal expansion should be selected which can moderate the interface failure in the certain degree.

Abstract: The content of stabilizer in gas chromatography to detect the stabilizer content in different aging time of the propellant GLQ, and the analysis of testing and statistical data of the measured experimental data. The results show that, the content of centralite in propellant GLQ with aging time decreased, with changing of propellant GLQ stability with time. Therefore, using the gas chromatography to test the content of the centralite , and judging the stability of propellant GLQ is feasible.