Advanced Materials Research Vol. 680

Abstract: Both the formation and migration energies of a single vacancy migrating intra- and inter-layer of the CuAg-terminated (001) surface or Cu-terminated (001) surface for Cu3Ag ordered alloy have been calculated by using the modified analytical embedded-atom method (MAEAM) with the molecular dynamics (MD) method. The surface effects on the vacancy formation and migration are all down to 6L for the CuAg-terminated (001) surface, but is respectively down to 5L and 6L for the Cu-terminated (001) surface. The vacancy energetically formed in the 1L. There is a vacancy aggregation tendency in the 1L as well as in the bulk the Cu vacancy is easier to be formed than the Ag vacancy.

Abstract: Here, modified analytic embedded atom method (MAEAM) has been utilized to simulate size effect and surface properties of aluminum (Al) nanoparticles. According to the simulation results, we can find that lattice parameter and excess stored energy are size dependent. The simulated excess stored energy ranges from 2.12 to 57.61 kJ/mol, which is in the same order of magnitude with experiment results; surface energy of Al nanoparticles ranges from 0.78 to 1.10 J/m2, which is not invariant but size related. Furthermore, non-uniform lattice distortion has been observed in Al nanoparticles, and mainly concentrates in the first and second shell of surface layers. Theoretical research based on our simulation results provides a novel method to predict excess stored energy of metallic nanoparticles.

Abstract: Resin in the foundry polyurethane binder is asked to be phenylic phenolic resin.The composition of the resin influences the capability of the polyurethane binder.In this paper.We studied on the synthesizing phenylic phenolic resin and obtained the better optimal technology conditions as following: used feculent point （80~90°C）to terminate the experiments;the optimal molar ratio of phenol to formaldehyde is from1∶1.5 to 1∶1.75;the formaldehyde concentration is 50%;the amount of catalyst is 0.05%~2% of the phenol.Phenylic phenolic resin that we get can enhance the strength of foundry cores and molds obviously.

Abstract: In this paper, the effect of ultrasonic wave on sizing materials is analyzed to optimize sizing properties. To give an overall view on the advantages of ultrasonic wave treatment in mixing and cooking , a range of solid contents are taken into account. By comparing with the traditional method of mixing and cooking, the relationships between sizing materials’(s) gelatinization temperature and time ,viscosity and viscosity stability are discussed. Experimental results have demonstrated that a certain ultrasonic frequency ( 40kHz ) in mixing and cooking method can reduce the gelatinization temperature and time, lower the viscosity of sizing solutions and increase viscosity’s stability.

Abstract: The ageing process of a Cu-2.1Ni-0.5Si-0.2Zr-0.05Cr alloy in the temperature range from 673 K to 773 K is investigated in this research. The phase transformation process, electric conductivities and mechanical properties during the ageing process are also studied by experimental methods. The precipitation sequence during the aging process of Cu-Ni-Si alloy is GP zone→ (Cu,Ni)3Si→ δNi2Si phase. The conductivity of the aged specimen increases from 20% IACS to 40-45% with prolonging time during aging process in the temperature range from 673 K to 773 K. The dynamic curve of precipitation is obtained by Avrami-equations, based on which the increase of yield strength can be estimated according to Orowan mechanism. Experimental data have been compared with the calculated results in this paper, indicating this method is reasonable, suggesting that strengthening is mainly attributed to Orowan by passing mechanism.

Abstract: The present work shows the results of investigation on the effects of sintering temperatures of (Mg0.25Mn0.1Zn0.65)Fe2O4 ferrite on its sintered density, initial permeabilty, resistivity and microstructure. To achieve better sintered density and initial permeabilty, the sintering temperature should be ≥1200oC. However, the higher sintering temperature results in larger the grain size, which causes the reduction of the resistivities of Mg-Mn-Zn ferrites. Furthermore, the resistivities of samples are environmental temperature sensitive, and possibly possess the similar function of NTC thermistor over the testing range 25-225oC.

Abstract: Experimental choose methyl-trichlorosilane, di-methyl-dichlorosilane and phenyl trichlorosilane synthetic organic silicon resin, add white mica powder, aluminum silicate, titanium pigment, zinc phosphate as packing, system high temperature insulation coating. For after high temperature resistant coating surface coating of tin model coating physical mechanical properties and high temperature resistant, heat insulation temperature difference of performance test, the results indicate that the system of high temperature resistant coating resistant to 400 ~ 500 °C high temperature, and has good high temperature resistance, heat insulation performance, etc.

Abstract: In this paper, a prediction model of the mechanical properties of composite materials has been proposed based on the ant colony neural network. The mechanical properties of the materials are the common problems that the various materials must be involved in the practical applications. The testing of the mechanical properties of the composite materials is of great significance to the development and the progress of the theory and the practice of composite materials. The ant colony algorithm takes advantage of the optimization mechanisms of ant colony, which has a strong ability to find the global optimal solution. The candidate group mechanism is added in the ant colony algorithm and the weights of the artificial neural network are trained through using the improved ant colony algorithm. This model has a strong adaptive ability and can be used in the prediction of the mechanical properties of composite materials. Then, the efficiency of the testing of mechanical properties can be improved.

Abstract: Five kinds of elastic knitted fabrics are purchased commercially for physical-mechanical properties testing, which including tensile properties, shearing properties, bending properties, compression properties and surface characteristics. Objective assessment the physical-mechanical properties of elastic knitted fabrics at its course and warp direction, respectively. And the influence of elastic fiber content on its properties is analyzed. The fabric with higher elastic fiber content has lower value in tensile force (F), elasticity modulus (E), shearing stiffness (G) and bending stiffness (B), also lower value in MIU, MMD and SMD, but higher value in tensile resilience (Re), compression linearity (LC) and compression energy (WC). The results will be the basic data for quantitatively analysis of relationship between physical-mechanical properties and performance of compression garment.