Papers by Author: Guang Yang

Abstract: TiC reinforced titanium matrix functionally graded materials （FGM） has been produced by processes of laser metal deposition through changing the powder feed rate of Ti and Cr3C2 powder. The OM, SEM, EDS methods were used to analyze the components and microstructure of the coatings. Microhardness and wearing resistance at room temperature of the FGM coating were examined by microhardness tester and wear tester respectively. The results show that FGM coating reinforced by in-situ TiC apparently improved hardness of Ti alloy; the microhardness can reach HV1100, and present gradient distribution along deposition direction. Dry sliding wear properties of these FGM coatings have been compared with substrate materials wearing. The observed wearing mechanisms are summarized and related to detailed microstructural observations. The results show the wear resistance of the coating can be improved by 46.6 times.

Abstract: To increase the strength and erosion resistance of Copper Crystallizer, the system based on Laser Metal Deposition (LMD) process was proposed to clad nickel-based alloy on its surface. With the optimal processing parameters ascertained by large numbers of experiments, the crystallizer was clad nickel-based alloy. The morphology and the microstructures of the cladding layers and bonding interface were analyzed by energy dispersive spectrometer and scanning electronic microscopy. The result shows that the bonding interface realizes the metallurgic and tight bonding.

Abstract: Constructing the topology of STL file efficiently is a key factor to improve the efficiency of slicing algorithm. In this paper a topology construction algorithm based on Standard Template Library set containers and a rapid slicing algorithm are developed. The algorithm developed removes a large number of redundant vertices, and only calculates intersection per triangular facet with slice plane once, and attains another point of intersection directly from the adjacent relations. In addition, the algorithm can reduce the times of traversing and sorting for the triangular facets, and also the times of calculation of intersection in the slicing processes, which results in the simplification of the process of constructing the slice contour, consequently the efficiency of the slicing algorithm is improved.

Abstract: In order to investigate the effect on manufacturing quality of focus position misalignment between laser beam and powder convergence in laser metal deposition shaping (LMDS) processing, several experiments including single-track monolayer, straight thin-wall and ring thin-wall were made. The measurements and analysis on shape, size and surface quality of the experiment parts were carried out. An omnidirectional detecting method to check the misalignment of focus position was brought forward and tested. The results indicate that the misalignment of focus position directly affects the quality of shaping parts and shows the regularity, the detecting method can easily detect the focus position misalignment on random direction and angle and guide the adjustment on them.

Abstract: The Ni60A powder was clad on the copper by the laser through coaxial power feeding. The hardness and erosion resistance of the substrate and the cladding layer were measured and made contrasts. The morphology and the microstructures of the cladding layer were analyzed by scanning electronic microscopy as well as the microstructure of bonding interface. The contents of major elements in the bonding interface were studied by energy dispersive spectrometer. Moreover, large amount of (Cu and Ni) solid solution formed a metallurgic and tight bonding with the good dilution between the substrate and cladding layer.