Advanced Materials Research Vols. 418-420

Abstract: In this paper, epitaxial growth on Ni-based single crystals was achieved by using spark deposition and laser powder deposition. Different Ni-based substrates, such as CMSX-4, TMS 138A as well as deposition materials: NiCrAl, Rene N4 and modified 4.5th generation single crystal alloys were used. The deposited layers were analysed by laser confocal microscopy, FEG-SEM, X-ray and electron backscatter diffraction (EBSD), had very little dilution and epitaxial growth was confirmed for the deposits made using Rene N4 electrodes. The deposition time at 100 V voltage, 850 W power and 110 Hz frequency was 3min and the layer thickness varied from 0.3 to 0.5 mm. Cracks were observed in certain areas with the formation of stray grains. In order to investigate the influence of the laser processing during multiple build up, specimens with one and ten layers were manufactured. The total layer thickness on substrates was 0.3 mm and 2 mm, respectively. The processing parameters were: laser power of 500 W, laser beam diameter of 0.6 mm and the z displacement was equal to 80% of the layer height. The laser deposition also resulted in successful epitaxial growth and minimal defects (pores or cracks), however the clads presented high dilution.

Abstract: According to the properties of the CNC precision internal grinding, the Human-machine interface system for the CNC based on industrial-grade touch device is proposed in this paper. Based on analyzing the human-machine interface system on the whole, each module is described in detail. The whole human-machine interface system is friendly, convenient and flexible, which meet the function requirements of embedded CNC precision internal grinder.

Abstract: Abstract: The magnetic abrasive finishing (MAF) process which was introduced during the late 1940s has emerged as an important non-traditional metal finishing process. The process has found applications in a wide range of fields such as aerospace, medical, electronics, precision dies and moulds as a part of their manufacturing activities. Magnetic abrasive grit size, magnetic field intensity, magnet & workpiece gap, relative speed between workpiece & magnet, vibration of workpiece/magnet are the principal parameters that control the surface characteristics. MAF is the process that is being developed for efficient & precision finishing upto nanolevel of cylindrical or flat workpieces made of hard to machine materials. This review provides an insight into the fundamental parameters and creates a better understanding of this finishing process, with the objective of helping in the selection of optimum machining parameters for finishing of varied workpieces in practice.

Abstract: Mn_xZn_1-XO Crystal was synthesized by hydrothermal method in this work.The experimental parameters for hydrothermal synyhesis were:Mineralizer concentration 3mol•L^-1KOH, the fill factor 35%, temperature 430°C, Zn(OH)₂ doped with MnO₂ as precursor, and the reaction time 24 hours. The Mn concentration in crystal was determined by X-ray EDS. The atomic percentage of Mn in crystal increases as the concentration of MnO₂ in precursor increased. The maximum atomic percentage for Mn is over 2%. The morphology shows characteristics of hexagonal prism of pure ZnO crystal. The exposed faces are hexagonal faces m｛10 0｝, hexagonal cone faces p｛10 1｝, negative polar faces ｛000 ｝and positive polar faces｛0001}. The diameters of the crystals are 50-200μm，the heights are 20-100μm.

Abstract: NC incremental sheet metal forming process is a flexible process which is to form the sheet point by point on NC forming machine according to the prepared program .The forming principle of NC incremental sheet metal forming process is presented. The strain is analysed. A formula of strain calculation is drawn in the NC incremental sheet metal forming process and verified by web experiment.

Abstract: There are many methods of refining of metallurgical grade silicon (MG-Si). In this paper, the purification of MG-Si by slag and acid leaching treatment respectively is investigated. It is found that the main metallic impurities in MG-Si, such as Fe、Al、Ca、Ni、Ti，and nonmetallic elements, such as P、B, precipitated in Si-Ca phase, which is dissolved by acid easily. The influence of different ratio of slag/silicon upon removal rate of boron also be researched As well as, the effect of the cooling speed of the molten silicon on removal of P by acid treatment is researched and it indicated that the slower of cooling speed, the best effect removal of P is up to,There are many methods of refining of metallurgical grade silicon (MG-Si). In this paper, the purification of MG-Si by slag and acid leaching treatment respectively is investigated. It is found that the main metallic impurities in MG-Si, such as Fe、Al、Ca、Ni、Ti，and nonmetallic elements, such as P、B, precipitated in Si-Ca phase, which is dissolved by acid easily. The influence of different ratio of slag/silicon upon removal rate of boron also be researched As well as, the effect of the cooling speed of the molten silicon on removal of P by acid treatment is researched and it indicated that the slower of cooling speed, the best effect removal of P is up to

Abstract: Al-5.8%Zn-1.63%Mg-2.22%Cu-0.12%Zr powders were manufactured by gas atomization process. The effect of temperature on microstructural evolution of the powders was investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). On reheating the atomized powders into semisolid state, the phase chemistry and quantity of liquid were typically changed as the system established equilibrium. As the heat treated temperature was increased from 550 °C to 620 °C, the amount of η (MgZn2) phase decreases and a great number of particles Al2Cu precipitates in the powders interior. The inter-diffusion of species will be the main factor. Considering the factors of microstructure, 600 °C is determined to be the best semi-solid forming temperature.

Abstract: The effects of different annealing technique on the static recrystallization, microstructure, mechanical properties and fraction mechanism of AZ31B magnesium alloy sheets are investigated. High toughness and high formability of AZ31B magnesium alloy sheets are achieved by researching how to optimize annealing technique to improve the microstructure and mechanical properties. The results show that better matching of strength and toughness are obtained, and the sheets have synthetically excellent mechanical properties when adopting the annealing temperature at the range of 320°C to 380°C, and the annealing time is near to one hour.

Abstract: Integrated multilayer wrapped pressure vessel is widely used in process industrial production. In allusion to its manufactural process and structural characteristics as well as considering the frictional force between the laminates in the relative displacement of the laminates, the calculation formulae in the laminate or the inner cylinder prestressed by the wrapping force of the hydraulic manipulator were derived by principles of mechanics. The investigative results of the prestress distribution in the integrated multilayer wrapped vessel structure have a certain direct significance for its actual manufacture and insuring its manufactural quality.

Abstract: An innovative type of one-point rolling contact fatigue (RCF) machine was developed in order to investigate crack initiation and propagation in metals. The microstructural changes and propagation of subsurface cracks during rolling contact in specimens tested by using the new device were studied by laser confocal microscope and X-ray diffraction. It was shown that this new method presents several important advantages compared to the conventional thrust type RCF machines.