Applied Mechanics and Materials Vols. 716-717

Abstract: The grain refinement and relative strengthening of rare earth element Sm in magnesium alloy AZ61 has been investigated. The results show that high melting point Al₂Sm phase forms in AZ61 alloy with the addition of 2wt.% Sm. It leads to the refinement of grain size and enhances the strength of AZ61 alloy.

Abstract: A facile method for the synthesis of size-and shape-controlled CuInS₂ semiconductor nanocrystals was developed by thermolysis of a mixed solution of Cu (acac)₂, In (acac)₃ and dodecanethiol at 200 °C. By adjusting the reaction time, CuInS₂ nanocrystals with size of ~2 to ~6 nm were obtained. The as-prepared nanocrystals were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), UV-vis absorption and photoluminescence (PL) spectroscopy. The nanocrystals solutions exhibit tunable absorption and PL spectra with the absorption edge ranging from 450 to 750 nm while the PL emission peaks from 660 to 700, indicting a strong size-dependent quantum confinement effect. The proposed synthesis strategy developed in this work may be used as a general process for other metal chalcogenides nanocrystals and may have a bright application prospects in different areas, such photovoltaic application, in the future.

Abstract: A quantitative structure–property relationship (QSPR) model for predicting the standard net heat of combustion () was developed based on the ant colony optimization (ACO) method coupled with the partial least square (PLS) for variable selection. Five molecular descriptors were screened out as the parameters of the model, which were finally constructed using multi-linear regression (MLR) method. A reliable model of five parameters for predicting the of esters was established, which can provide some help for engineering to predict the based on only their molecular structures.

Abstract: In this paper, the effect of welding processes such as friction stir welding (FSW), laser beam welding (LBW) and pulsed current gas tungsten arc welding (PCGTAW) on comprehensive mechanical properties of AZ31B magnesium alloy was reviewed. Among the three different welding processes, the LBW joints showed superior comprehensive properties to FSW and PCGTAW joints. The formation of very fine grains in weld region, higher fusion zone hardness, uniformly distributed finer precipitates were the main reasons for superior comprehensive mechanical performance of LBW joints compared to PCGTAW and FSW joints.

Abstract: In this paper, the machining surface quality is analyzed. The factors impacting the surface quality of machining are pointed out such as wear resistance, fatigue strength, corrosion resistance, cooperate with quality etc. Measures to improving the machining surface quality are put forward including cutting tool, work piece material, cutting condition, processing method; reduce the machining deformation of surface strengthening, and residual stress in order to apply the rule to control the machining process, finally achieve the purpose of improving surface quality and product performance. The cold work hardening of the surface layer is analyzed. It will be certain guidance for engineering practice.

Abstract: The research on curing processes in Resin Transfer Molding is helpful to control the chemical reaction, material structures and properties.In this paper, the chemical kinetic equations of curing processes, crosslinked structure parameters equations and the temperature basic equations are founded in the curing processes. The finite element method is adopted to simulate the curing processes to analyze the influence and changes of temperature, curing ratio and crosslinking degree.

Abstract: The evolution regularity of the optical properties and electronic structure for ZnO hexagonal phase is studied under high-pressure, by using first-principles plane wave pseudo-potential method. The method is based on density functional theory (DFT) within the generalized gradient approximation (GGA) approaches. The calculation reveals that the valence band and the conduction band move to the direction of low energy and the direction of high energy by an increase of pressure, respectively, and thus the band gap is enlarged. The results of calculate also show that the energy band structure of ZnO hexagonal phase changes and the band gap is broadened with the increasing of pressure, which results in the move of the optical absorption margin and the optical absorption peak towards the aspect of the high energy.

Abstract: . The systematic experiments for cutting remanufacture deposited materials have been finished. The results show that the deposited materials can be divided into two parts on the view of machining process:surface layer and dense layer. One of the distinctive features on surface layer is impacts to cutting tools in the process. And the process of dense layer cutting is similar with homogeneous material. On the basis of above, the paper puts forward the method which adopts different processing phases for deposited materials.

Abstract: Tread rubber is formed with two purposes. A separate wire beneath the tread rubber powder processing to reduce tool wear Dayton speed , and the other is to reduce tire division cutting the number of large particles of plastic blocks to shorten the grinding process . Tread rubber processing is in the tread ring body segmentation . Ring with the tread surface of the body as clamping plane. Clamping the tread ring body is an elastic expansion of the clamping piece . Processing machinery designed modular form while completing the tread rubber strip on the mouth of cutting and peeling colloids . In front of the tool cutting point increase in the formation pressure roller is smooth plastic surface processing point . Limiting processing to control the separation of the tread rubber tread rubber particles.

Abstract: ordinary carbon steel hardness and life is difficult to achieve blanking dies and drawing dies requirements. In the surfacing alloy steel and alloy steel base can improve the surface hardness and durability of the mold. To reduce the use of electric arc welding carbide decomposition and burn in the shielding gas . Welding mold base structure to meet the requirements of the welding . Mold heat treatment after welding specifications and hardness to meet the processing requirements and use of strength requirements. Welding process design mold substrate heating requirements and the requirements of the solder layer thickness and the thickness between layers allocation.