Al2O3 fiber （Al2O3f） and SiC particle （SiCp） hybrid metal matrix composites （MMCs） were fabricated by squeeze casting method.The tests were carried out using a pin-on-disk friction and wear tester by sliding the...Al2O3 fiber （Al2O3f） and SiC particle （SiCp） hybrid metal matrix composites （MMCs） were fabricated by squeeze casting method.The tests were carried out using a pin-on-disk friction and wear tester by sliding these pin specimens at a constant speed of 0.36 m/s （570 r/min） against a steel counter disk at room temperature,100 C and 150 C,respectively.To observe the wear characteristics and investigate the wear mechanism,the morphologies of the worn surfaces and specific wear rate were analyzed by using scanning electron microscope （SEM） and Arrhenius plots.Moreover,the effects of fiber orientation and hybrid ratio were discussed.展开更多
The effect of rotational speed in the friction surfacing of nickel-aluminide reinforced Al-Zn-Mg-Cu alloy matrix composite on commercially pure aluminum was investigated. The nickel-aluminide reinforcement was fabrica...The effect of rotational speed in the friction surfacing of nickel-aluminide reinforced Al-Zn-Mg-Cu alloy matrix composite on commercially pure aluminum was investigated. The nickel-aluminide reinforcement was fabricated by in-situ methods based on adding nickel powders to Al-Zn-Mg-Cu alloy melt during the semi-solid casting process.The findings showed that an increase in the rotational speed from 600 to 1000 r/min raised the coating efficiency from 65% to 76%. Besides, there was no significant difference between coating efficiencies in the coating with and without nickel-aluminide. The outcomes showed that if the coating was applied at a rotational speed of 1000 r/min, a traverse speed of 100 mm/min, and an axial feeding rate of 125 mm/min, the hardness and shear strength of the substrate increased by up to 225% and 195%, respectively. But the wear rate of the substrate dropped by 75%. Although the hardness of the coating containing nickel-aluminide increases by up to 32% compared to the coating without nickel-aluminide, nickel-aluminide does not affect the thermal stability of the coating.展开更多
The effect of brake oil on sliding behavior of carbon/carbon(C/C) and carbon/carbon-silicon carbide(C/C-SiC) composites was investigated with the variation of laminate orientation and surface conformity. The partial a...The effect of brake oil on sliding behavior of carbon/carbon(C/C) and carbon/carbon-silicon carbide(C/C-SiC) composites was investigated with the variation of laminate orientation and surface conformity. The partial and low conformity contacts with the normal and parallel orientations of laminates were considered. The normal load was varied from 50 to 90 N in a step of 10 N. The friction and wear behavior was investigated under reciprocating sliding conditions. The results showed that friction coefficient and wear loss of composites with normal orientation of laminates were larger as compared to those of composites with parallel orientation of laminates. C/C composites with normal orientation of laminates yielded the highest value of friction coefficient. Wear loss decreased by a maximum of 78%, and friction coefficient decreased by a maximum of 49% in low conformity contacts as compared to partial conformity contacts. The presence of brake oil reduced the adhesion tendency of compacted wear debris because the formation of friction film was difficult, and thus, friction behavior was affected. The wear debris retention between the contact surfaces due to confined area motion in reciprocating sliding depicted the tribological behavior.展开更多
基金supported by Changwon National University in 2010the Korea Research Foundation Grant (KRF-2008-D00005) funded by the Korean Government (MOEHRD Basic Research Promotion Fund)
文摘Al2O3 fiber （Al2O3f） and SiC particle （SiCp） hybrid metal matrix composites （MMCs） were fabricated by squeeze casting method.The tests were carried out using a pin-on-disk friction and wear tester by sliding these pin specimens at a constant speed of 0.36 m/s （570 r/min） against a steel counter disk at room temperature,100 C and 150 C,respectively.To observe the wear characteristics and investigate the wear mechanism,the morphologies of the worn surfaces and specific wear rate were analyzed by using scanning electron microscope （SEM） and Arrhenius plots.Moreover,the effects of fiber orientation and hybrid ratio were discussed.
文摘The effect of rotational speed in the friction surfacing of nickel-aluminide reinforced Al-Zn-Mg-Cu alloy matrix composite on commercially pure aluminum was investigated. The nickel-aluminide reinforcement was fabricated by in-situ methods based on adding nickel powders to Al-Zn-Mg-Cu alloy melt during the semi-solid casting process.The findings showed that an increase in the rotational speed from 600 to 1000 r/min raised the coating efficiency from 65% to 76%. Besides, there was no significant difference between coating efficiencies in the coating with and without nickel-aluminide. The outcomes showed that if the coating was applied at a rotational speed of 1000 r/min, a traverse speed of 100 mm/min, and an axial feeding rate of 125 mm/min, the hardness and shear strength of the substrate increased by up to 225% and 195%, respectively. But the wear rate of the substrate dropped by 75%. Although the hardness of the coating containing nickel-aluminide increases by up to 32% compared to the coating without nickel-aluminide, nickel-aluminide does not affect the thermal stability of the coating.
文摘The effect of brake oil on sliding behavior of carbon/carbon(C/C) and carbon/carbon-silicon carbide(C/C-SiC) composites was investigated with the variation of laminate orientation and surface conformity. The partial and low conformity contacts with the normal and parallel orientations of laminates were considered. The normal load was varied from 50 to 90 N in a step of 10 N. The friction and wear behavior was investigated under reciprocating sliding conditions. The results showed that friction coefficient and wear loss of composites with normal orientation of laminates were larger as compared to those of composites with parallel orientation of laminates. C/C composites with normal orientation of laminates yielded the highest value of friction coefficient. Wear loss decreased by a maximum of 78%, and friction coefficient decreased by a maximum of 49% in low conformity contacts as compared to partial conformity contacts. The presence of brake oil reduced the adhesion tendency of compacted wear debris because the formation of friction film was difficult, and thus, friction behavior was affected. The wear debris retention between the contact surfaces due to confined area motion in reciprocating sliding depicted the tribological behavior.
