In order to improve dry sliding wear resistance of pure aluminum against steel, aluminum-based composites reinforced with different contents of SiC,MoS2 and SiC/MoS2 particles were synthesized by press and sintering o...In order to improve dry sliding wear resistance of pure aluminum against steel, aluminum-based composites reinforced with different contents of SiC,MoS2 and SiC/MoS2 particles were synthesized by press and sintering of the corresponding powder mixtures. The microstructural evaluations showed a dense microstructure which were in good agreement with the result of density and hardness measurements. The results of pin on disk wear tests performed against an AISI 52100 steel pin at a constant load and sliding velocity showed that there was a critical content for both types of the reinforcements at which the lowest wear rate was obtained, i.e. 10 vol.% and 2 vol.%, respectively,for Al/SiC and Al/MoS2 composites. However,the lowest wear rate and friction of coefficient were attained for Al/10 SiC/2 MoS2 hybrid composite. According to the scanning electron microscope observations, the predominant wear mechanism was changed from adhesion to abrasion mostly whenMoS2 particles were incorporated in the pure aluminum. Mild delamination was identified as the main wear mechanism for Al/SiC and Al/SiC/MoS2 composites. The frictional traces and worn surfaces of Al/SiC/MoS2 composites approached to those of Al/SiC composites,indicating the dominant role of SiC particles in tribological behavior of the hybrid composites.展开更多
A new method combining the slider-crank mechanism dynamic(SCM)and crankpin bearing(CB)lubrication models is proposed to analyze the effects of CB dimensions and engine speed on the lubrication efficiency and friction ...A new method combining the slider-crank mechanism dynamic(SCM)and crankpin bearing(CB)lubrication models is proposed to analyze the effects of CB dimensions and engine speed on the lubrication efficiency and friction power loss(LE-FPL)of an engine.The dynamic and lubrication equations are then solved on the basis of the combined model via an algorithm developed in MATLAB.To enhance the reliability of the research results,the experimental data of combustion gas pressure is applied for simulation.The load bearing capacity(or oil film pressure),friction force,friction coefficient,and eccentricity ratio of the CB are selected as objective functions to evaluate the LE-FPL.The effects of engine speed,bearing width,and bearing radius on the LE-FPL are then evaluated.Results show that reductions in engine speed,bearing width,or bearing radius can decrease the FPL but reduce the LE of the engine and vice versa.In particular,the LE-FPL can effectively be improved by slightly reducing the bearing width and bearing radius or maintaining engine speed at 2000 r/min.展开更多
文摘In order to improve dry sliding wear resistance of pure aluminum against steel, aluminum-based composites reinforced with different contents of SiC,MoS2 and SiC/MoS2 particles were synthesized by press and sintering of the corresponding powder mixtures. The microstructural evaluations showed a dense microstructure which were in good agreement with the result of density and hardness measurements. The results of pin on disk wear tests performed against an AISI 52100 steel pin at a constant load and sliding velocity showed that there was a critical content for both types of the reinforcements at which the lowest wear rate was obtained, i.e. 10 vol.% and 2 vol.%, respectively,for Al/SiC and Al/MoS2 composites. However,the lowest wear rate and friction of coefficient were attained for Al/10 SiC/2 MoS2 hybrid composite. According to the scanning electron microscope observations, the predominant wear mechanism was changed from adhesion to abrasion mostly whenMoS2 particles were incorporated in the pure aluminum. Mild delamination was identified as the main wear mechanism for Al/SiC and Al/SiC/MoS2 composites. The frictional traces and worn surfaces of Al/SiC/MoS2 composites approached to those of Al/SiC composites,indicating the dominant role of SiC particles in tribological behavior of the hybrid composites.
基金The National Key Research and Development Plan(No.2019YFB2006402)the Key Project of Scientific Research Plan of Hubei Polytechnic University(No.21xjz02A)the Open Fund Project of Hubei Key Laboratory of Intelligent Transportation Technology and Device,Hubei Polytechnic University(No.2020XY105,2020XZ107).
文摘A new method combining the slider-crank mechanism dynamic(SCM)and crankpin bearing(CB)lubrication models is proposed to analyze the effects of CB dimensions and engine speed on the lubrication efficiency and friction power loss(LE-FPL)of an engine.The dynamic and lubrication equations are then solved on the basis of the combined model via an algorithm developed in MATLAB.To enhance the reliability of the research results,the experimental data of combustion gas pressure is applied for simulation.The load bearing capacity(or oil film pressure),friction force,friction coefficient,and eccentricity ratio of the CB are selected as objective functions to evaluate the LE-FPL.The effects of engine speed,bearing width,and bearing radius on the LE-FPL are then evaluated.Results show that reductions in engine speed,bearing width,or bearing radius can decrease the FPL but reduce the LE of the engine and vice versa.In particular,the LE-FPL can effectively be improved by slightly reducing the bearing width and bearing radius or maintaining engine speed at 2000 r/min.
