Papers by Author: Hui Huang

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Authors: Juan Liu, Hui Huang, Xi Peng Xu
Abstract: In this paper, the influences of abrasive size, abrasive concentration and admixture way on the abrasive dispersing of the sintered ultra-fine diamond tool were systemically investigated. Then, a comparison of the abrasive dispersing was made between the sintered ultra-fine diamond tool and the newly developed ultra-fine diamond tool by gel technique. ESEM was applied to observe the abrasive dispersing of the sintered and gel-coupled ultra-fine diamond tools. The abrasive dispersing was quantitatively evaluated by the statistic laws of grit spacing in a certain area. Experimental results indicated that the dispersing was mainly influenced by the abrasive size. The ultra-fine abrasive tended to agglomerate with the decrease of grit sizes due to the increase of surface energies. The abrasive concentration and admixture way had few effects on abrasive dispersing. The abrasive dispersing of the sintered diamond tool was worse compared with the gel-coupled ultra-fine diamond tool.
Authors: Guo Qing Zhang, Hui Huang, Xi Peng Xu
Abstract: An experimental investigation was carried out to braze diamond abrasives onto thin steel wires, in which case the brazing was conducted in the vacuum and under high temperatures by using a nickel-based powder as brazing alloy. The morphologies and microstructures of the brazed wires were observed and the comprehensive mechanical properties of the brazed wires were tested. The brazed wires were also used to cut such brittle materials as ceramics, glass, and natural stone. It is shown that a typical phenomenon of brazing alloy’s climbing around the diamond grains was observed in brazing the wires. Through observing the cross-section of brazed wires, it is observed that there is a good bonding between the brazing alloy and the body of steel wires. The crystal grains of the steel wires grew significantly after brazing. Through observing the morphologies of the diamond wires and the surfaces of four workpiece materials, few diamond pull-outs were found on the wires and the kerfs on the workpiece materials were basically flat.
Authors: Hui Huang, Jian Yun Shen, Xi Peng Xu, Hong Jun Xu
Authors: Qing Ru Lu, Hui Huang, De Bing Chen
Abstract: Strengthening the study on whiskers influence on the reliability of lead-free soldering can improve welding technology and contribute to the overall development of the electronics industry. This paper provides an overview of the study on lead-free solder technology and development, summaries the materials, processes and other reliability issues and welding reliability problems of lead-free solder, finally gives an overview of the research status of whiskers formation mechanism and reliability.
Authors: Guo Qin Huang, Hui Huang, Xi Peng Xu
Abstract: An investigation was undertaken to elucidate the mechanisms for the fracture failure of brazed diamonds in wire sawing. Diamonds were brazed by high-frequency induction in vacuum. The changes of compressive strength and the appearances of the diamonds at different brazing temperatures were obtained. The morphologies of the diamonds after sawing were also observed. Together with the stress analysis of a brazed grit, it is found that the fracture failure of brazed grit is the result of the brittle fracture happening on the root section of the grit, the interface between the grit and the brazing alloy. The degradation of mechanical properties of grits in brazing is a key factor to the reduction of their resistance to fracture. Lower machining forces as well as grit exposure are in favor of preventing grits from fracture.
Authors: Kui Yuan Feng, De Kui Mu, Xin Jiang Liao, Hui Huang, Xi Peng Xu
Abstract: In this paper, a preliminary study in the wetting behavior and interface reaction between active Sn-Ag-4Ti solder alloy and C-plane sapphire was given. An in-situ observation of Sn-Ag-4Ti alloy on C-plane sapphire revealed a decrease in contact angles at temperature close to 550°C. Moreover, sapphire/sapphire and sapphire/copper sandwich joints were brazed using Sn-3.5Ag-4Ti alloy at 500 oC, 550°C and 600 °C to investigate the microstructure evolution and interface reaction. Microstructure characterization and element analysis indicated that the temperature affected the diffusion of active Ti element by modifying the formation of Sn-Ti intermetallics compounds in Sn-Ag-Ti solder alloy. The absorption of Ti together with the release of Al from sapphire suggested the interface reaction between Sn-Ag-Ti alloy and sapphire was triggered at 550°C.
Authors: Yuan Li, Hui Huang, Xi Peng Xu
Authors: Hua Guo, Guo Qin Huang, Hui Huang, Xi Peng Xu
Abstract: An investigation is reported of the effects of three different coatings onto diamonds in the composites for the beads of wire saws. The matrix of the composites contained 80% (w/w) cobalt. Ti, W, and W-Co were coated onto diamond surfaces respectively and then incorporated into the matrix. The mixed powders were hot-pressed to form the specimens for bending tests. Coupled with the results of bending tests and the strength of coated diamonds, the coatings of W were found to be best among the three coatings. Further experiments indicated that the thickness of W-coatings onto the diamonds should be controlled around 10(m in order to obtain an excellent retention of diamonds.
Authors: Yong Peng Li, Hui Huang, Xi Peng Xu
Abstract: Fixed-abrasive wire saw, with its ability to cut hard brittle material, such as silicon ingots, crystals and quartz, has emerged as a leading technology for production in semiconductor and photovoltaic industry. There are some defects in conventional fixed-abrasive wire saw such as significant low holding abrasive ability, low machining efficiency, high running costs, etc. A new fixed-abrasive wire, namely brazed diamond wires have been developed to overcome these problems. In this paper, brazed diamond wire were carried out to braze two different size diamond grits onto two different thin steel wires by using a nickel-based powder as brazing alloy. The mechanical properties of brazed diamond wire were evaluated by tensile and breaking twist experiment. The experimental results showed that the heating in the brazing process has litter influence on the wire mechanical properties. The addition of brazed alloy and diamond grits sharply decreased the wire mechanical properties significantly, both in the tensile strength and breaking twist angle. Bigger diamond grit would make the accumulation of brazed alloy which leaded to the deterioration of diameter consistency of wires.
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