Advanced Materials Research Vols. 472-475

Abstract: Abstract. The paper presents the results of a study concerned with the surface hardening of Inconel 625 alloys and Ni-base alloy powder on Monel alloy by electro spark deposition and laser cladding processes. The microstructure, the phase composition and the microhardness of samples are investigated by SEM, EDS, XRD and microhardness instrument. It is shown that, the matrix phase is mainly made up of dendritic structure (γ-Ni), interdendritic eutectic phase (Ni3(B,Fe,Si)) and some precipitates (Cr7C3, Cr23C6). Additional, the microhardness of laser cladding layer can be substantially increased, duo to formation of precipitates.

Abstract: Registration of 3-D shape is significant in quantizing the error between the part and its CAD model and evaluating the part's manufacturing accuracy. In the past, various improved methods of the iterative closest point (ICP) had been proposed in registration. However, without fine initial pose of point clouds, the ICP algorithm often could not converge to the best (or near best) solution. According to the characteristics of 3-D shape with free-form surface, a new method for registration of 3-D shape with free-form surface is given, by which there are not rigid requests in initial pose of point data and the 3-D shape model could be in arbitrary positions and orientations in space. To improve the efficiency and accuracy of solving, this method is divided into general registration and fine registration. General registration is to fit rapidly and roughly the measured point cloud to designing point cloud from CAD model by Imageware. Fine registration is to further accurately fit the two group points using genetic algorithm (GA). Case study is finally given for a work piece with free-form surface to show the effectiveness of the above method.

Abstract: This paper preliminarily explored and proved the feasibility of fabricating semisolid thixoforming billets for a hypereutectic Al-Si alloy (AlSi29Fe3) by severe plastic deformation (SPD) and semisolid remelting. In this paper, friction stir processing (FSP) was used to refine the coarse primary silicon particles and needle-shaped iron-rich phase of the hypereutectic Al-Si alloy. The results show that the semisolid thixoforming billets obtained by the above route contain fine spherical Al grains with mean size of 34m, and second-phase particles (both primary silicon and iron-rich intermetallic) of less than 10m. The microstructure is ideal non-dendritic semisolid structure. Therefore, SPD and remelting is a promising technology for the fabrication of semisolid thixoforming billets of the hypereutectic Al-Si alloy.

Abstract: A simple pitch error of lead screw error measurement based on the granite step gauge has been presented in this paper. This method has the advantages of easy operation, less time cost and also high accuracy. this method is expected to find wide applications in machine calibration, machine manufacture and error compensation.

Abstract: Through dimensional analysis of indentation parameters in this study, we propose an artificial neural network (ANN) model to extract the residual stress and strain-hardening exponent based on spherical indentation. The relationships between indentation parameters and the residual stress and material properties are numerically calibrated through training and validation of the ANN model. They enable the direct mapping of the characteristics of the indentation parameters to the residual stress and the elastic-plastic material properties. The proposed ANN model can be used to quickly and effectively determine the residual stress and strain-hardening exponent.

Abstract: The deposition of coatings on the surface of carbon fiber will be helpful to their applications. However, they are unsuitable to be deposited due to their low surface free energies, poor wettability and poor adhesions. The objective of this work is to modify carbon fibers by Dielectric barrier discharges(DBD)in ambient argon . The chemical and physical changes induced by the treatments on carbon fibers surface are examined using contact angle measurements and X-ray photoelectron spectroscopy (XPS). The interfacial adhesion of CF/EP composites are analyzed by a single fiber composite (SFC) for filament fragmentation test. The contact angles of the plasma-treated samples are visibly reduced than the untreated samples. XPS results reveal that the carbon fibers modified with the DBD at an atmospheric pressure show a significant increase in oxygen-containing groups, such as C–O,C=O and O–C=O. The results of SFC tests show that the treated carbon fibers composites could possess excellent interfacial properties with mixed resins. These results demonstrate that the surfaces of the carbon fibers samples are more active, hydrophilic and rough after plasma treatments using a DBD operating in ambient argon.

Abstract: Electrolysis and plasma polishing(EPP) is a new “green” technique that can efficiently polish metal workpieces and provide high-quality surface of the workpieces. In this paper, mechanism of EPP and why metal parts can be polished by EPP are expounded on by Streamer theory. EPP is a dynamic process consisting of oxidation and discharge. A precondition of EPP is that the removal rate of discharge is faster than oxidation. It is deduced from the mechanism and demonstrated experimentally that the material removal rate is direct proportion to the electric current density.

Abstract: Hot dip galvanizing is being widely used to the numerous constructional steels such as a guard rail of high way, various types of structural steel for manufacturing ship and for some other fields etc.. Recently, the cost of zinc is getting higher and higher, thus, a proper manufacturing process should be developed possibly to reduce the cost of production. one of hot dip galvanizing process, that is, flux solution immersion process is very important to control more effective coating. However, flux solution is deteriorated with increasing its using time because dissolved iron from structural steel due to continuous flux treatment was increasingly increased, which is resulted in coating badness and increment of dross. In this study, elimination of iron dissolved in flux solution was investigated with some types of inner solution which is added with additives such as seawater, NH4OH, NaOH, NH4Cl and thiourea, and electrolysis experiment was carried out with parameters of applied current density. For elimination of iron from flux solution, it is considered that inner barrel with separator should be filled with solution different from original flux solution which is involved in iron ion, that is, the inner solution which is made up seawater added with additives such as NH4Cl (5g), NaOH(0.5g) and thiourea(0.5g) is the most desirable solution to effectively extract iron from flux solution. An optimum applied current density for the most extraction effect of iron through electrolysis experiment is thought to be 20mA/cm2 .

Abstract: A set of structural composition and system composition of self-propelled submarine model which has already been used in experiments as well as the details of its long-wave controller and automation systems was introduced in this study. The feasibility of this technique applied to the model has been proved by real test in lake and the results derived from that will have some guiding significance to research on maneuverability of submarine which thus indicates that keep developing the self-propelled submarine model technique will for sure has a bright future.