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Yu J.,Hefei University of Technology | Yu J.,Anhui Research Center for Powder Metallurgy Engineering and Technology | Luo Z.,Hefei University of Technology | Yin Y.,Hefei University of Technology | And 2 more authors.
Zhongguo Jixie Gongcheng/China Mechanical Engineering | Year: 2013

The common method of wavelet threshold denoising for infrared image processing usually distorts the edge in image. A new method, combining the mathematical morphology edge detection and the wavelet threshold denoising, was presented and applied in denoising the infrared image of friction surface. Infrared image was processed through three steps: wavelet transformation, mathematical morphology edge detection in the high-frequency sub-band for determination the location of edge and threshold denoising. Experimental results show that this method can preserve more edge information, improve mean square deviation and peak signal-to-noise ratio. The intention of this approach is to improve the accuracy of the temperature measurement of the infrared images, thus it provides better technical support for measuring and analyzing friction temperature field with the high engineering values.


Jiao M.H.,Hefei University of Technology | Su B.W.,Hefei University of Technology | Ma S.B.,Anhui Research Center for Powder Metallurgy Engineering and Technology | Wan B.C.,Hefei University of Technology | Yin Y.G.,Hefei University of Technology
Applied Mechanics and Materials | Year: 2012

A new mixed method is adopted to make the powders mixed into bond particles, which is prepared for the PM iron-based sintered composites. The influences of phosphorus content on the physical properties and the frictional and wear properties of composites were analyzed in this paper. The morphology of frictional surface was confirmed by scanning electron microscopy. The results show the phosphorus addition may increase the matrix hardness and the anti-adhesion and anti-scratch behaviours significantly, and improve the anti-friction property and load carrying capacity of iron-based P/M composites. The composites containing 0.3 wt% of phosphorus has the optimal wear and frictional properties, and the self-lubricating performance is also improved obviously. © (2012) Trans Tech Publications, Switzerland.


Li Y.,Hefei University of Technology | Li Y.,Anhui Research Center for Powder Metallurgy Engineering and Technology | Cheng J.,Hefei University of Technology | Cheng J.,Anhui Research Center for Powder Metallurgy Engineering and Technology | And 4 more authors.
Fenmo Yejin Jishu/Powder Metallurgy Technology | Year: 2014

Soft magnetic Fe-Si powder cores were prepared using Fe-6.5Si powders as raw materials, multicomponent inorganic oxides as binders by warm compaction and heat treatment. Scanning electron microscope, vibration magnetometer survey analysis were used to analyze the density, microstructure and magnetic properties of the samples. The results indicate that the content of binders, compaction pressure and temperature would affect the properties of the Fe-Si powder cores. Green density of 6.34 g/cm3 of Fe-Si compacts can be reached with binder of 1.5%, the warm compaction temperature of 150°C and pressure of 900 MPa. The density of the Fe-Si cores by heat treatment in argon atmosphere at 720°C is 6.58 g/cm3, saturation induction is 1.26T and coercive force is 0.81 kA·m-1.


Yin Y.G.,Hefei University of Technology | Li Y.Y.,Hefei University of Technology | Zhang G.T.,Hefei University of Technology | Yin L.G.,Hefei University of Technology | Jiao X.N.,Anhui Research Center for Powder Metallurgy Engineering and Technology
Advanced Materials Research | Year: 2013

Cu-matrix bearing materials were prepared by powder metallurgy method and their mechanical properties were studied in present work. The continuity of copper alloy matrix was destroyed with the increase of Bi element. Because Bi is brittle phase and distributed in the copper alloy matrix grain boundaries as thin ribbon network. The hardness, crushing strength and impact toughness of copper-bearing materials were reduced with increase of the content of Bi. The mainly of Copper-bearing materials containing bismuth fracture are brittle intergranular fracture. When the Bi content is over 4wt%, the Bi has a relatively full distribution in the rich Bi phase of copper alloy matrix grain boundary like a chip mesh belt. As the further increase of Bi, the reduced trends of the mechanical properties of Cu-matrix bearing materials containing bismuth are slow down. because the role of fragmented Copper alloy matrix will not significantly increase with further increase of Bi. © (2013) Trans Tech Publications, Switzerland.


Jiao M.H.,Hefei University of Technology | Wan B.C.,Hefei University of Technology | Su B.W.,Hefei University of Technology | Ma S.B.,Anhui Research Center for Powder Metallurgy Engineering and Technology | Yin Y.G.,Hefei University of Technology
Advanced Materials Research | Year: 2013

Pre-configured powders were mixed uniformly through bonding granulation method. The boracic iron based self-lubricating composites with copper of different mass were prepared by the powder metallurgy press-sinter process. The tribological properties under different conditions of load were investigated on HDM20 end-face tribometer. The composite structure, the wear mechanism which copper affect the friction and wear behaviors of boracic iron based composites were analyzed by using X-ray diffraction, EDS and metallographic microscope. The results show that elementary copper which forming alloy phase could strengthen the combination of each phase in composites, playing the role of "binder", improve the tribological properties. The synergistic effect between the phases combination, hardness and strength of Cu-20w composite were observably, which lead to the excellent tribological properties synthetically. © (2013) Trans Tech Publications, Switzerland.

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