An attempt was made to synthesize Cu/B4C surface composite using friction stir processing（FSP） and to analyze the influence of tool rotational speed on microstructure and sliding wear behavior of the composite. The ...An attempt was made to synthesize Cu/B4C surface composite using friction stir processing（FSP） and to analyze the influence of tool rotational speed on microstructure and sliding wear behavior of the composite. The tool rotational speed was varied from 800 to 1200 r/min in step of 200 r/min. The traverse speed, axial force, groove width and tool pin profile were kept constant. Optical microscopy and scanning electron microscopy were used to study the microstructure of the fabricated surface composites. The sliding wear behavior was evaluated using a pin-on-disc apparatus. The results indicate that the tool rotational speed significantly influences the area of the surface composite and the distribution of B4C particles. Higher rotational speed exhibits homogenous distribution of B4C particles, while lower rotational speed causes poor distribution of B4C particles in the surface composite. The effects of tool rotational speed on the grain size, microhardness, wear rate, worn surface and wear debris were reported.展开更多
The effect of MoS2 lubricant particles on the microstructure, microhardness and tribological behavior of A413/SiCp surface composite, fabricated via friction stir processing （FSP）, was studied. For this purpose, ...The effect of MoS2 lubricant particles on the microstructure, microhardness and tribological behavior of A413/SiCp surface composite, fabricated via friction stir processing （FSP）, was studied. For this purpose, the FSP was carried out with tool rotational speed of 1600 r/min, tool travel speed of 25 mm/min and tool tilt angle of 3° through only a “single pass”. The optical and scanning electron microscopies, microhardness and reciprocating wear tests were used to characterize the samples. The results showed that the addition of MoS2 lubricant particles to A413/SiCp surface composite leads to the decrease of friction coefficient and mass loss. In fact, the generation of mechanically mixed layer （MML） containing MoS2 lubricant particles in A413/SiCp/MoS2p surface hybrid composite results in the reduction of metal-to-metal contact and subsequently leads to the improvement of tribological behavior.展开更多
Friction stir processing（FSP） was utilized to produce surface composites by incorporating nano-sized cerium oxide（CeO2） and silicon carbide（SiC） particles individually and in combined form into the Al5083 alloy ...Friction stir processing（FSP） was utilized to produce surface composites by incorporating nano-sized cerium oxide（CeO2） and silicon carbide（SiC） particles individually and in combined form into the Al5083 alloy matrix. The study signified the role of these reinforcements on microstructure and wear behavior of the resultant surface composite layers. The wear characteristics of the resultant mono and hybrid surface composite layers were investigated using a pin-on-disc wear tester at room temperature. The microstructural observations of FSPed regions and the worn out surfaces were performed by optical and scanning electron microscopy. Considerable grain refinement and uniform distribution of reinforcement particles were achieved inside the nugget zone. All the composite samples showed higher hardness and wear resistance compared to the base metal. Among the composite samples, the hybrid composite（Al5083/CeO2/SiC） revealed the highest wear resistance and the lowest friction coefficient, whereas the Al5083/SiC composite exhibited the highest hardness, i.e., 1.5 times as hard as that of the Al5083 base metal. The enhancement in wear behavior of the hybrid composites was attributed to the solid lubrication effect provided by CeO2 particles. The predominant wear mechanism was identified as severe adhesive in non-composite samples, which changed to abrasive wear and delamination in the presence of reinforcing particles.展开更多
文摘An attempt was made to synthesize Cu/B4C surface composite using friction stir processing（FSP） and to analyze the influence of tool rotational speed on microstructure and sliding wear behavior of the composite. The tool rotational speed was varied from 800 to 1200 r/min in step of 200 r/min. The traverse speed, axial force, groove width and tool pin profile were kept constant. Optical microscopy and scanning electron microscopy were used to study the microstructure of the fabricated surface composites. The sliding wear behavior was evaluated using a pin-on-disc apparatus. The results indicate that the tool rotational speed significantly influences the area of the surface composite and the distribution of B4C particles. Higher rotational speed exhibits homogenous distribution of B4C particles, while lower rotational speed causes poor distribution of B4C particles in the surface composite. The effects of tool rotational speed on the grain size, microhardness, wear rate, worn surface and wear debris were reported.
文摘The effect of MoS2 lubricant particles on the microstructure, microhardness and tribological behavior of A413/SiCp surface composite, fabricated via friction stir processing （FSP）, was studied. For this purpose, the FSP was carried out with tool rotational speed of 1600 r/min, tool travel speed of 25 mm/min and tool tilt angle of 3° through only a “single pass”. The optical and scanning electron microscopies, microhardness and reciprocating wear tests were used to characterize the samples. The results showed that the addition of MoS2 lubricant particles to A413/SiCp surface composite leads to the decrease of friction coefficient and mass loss. In fact, the generation of mechanically mixed layer （MML） containing MoS2 lubricant particles in A413/SiCp/MoS2p surface hybrid composite results in the reduction of metal-to-metal contact and subsequently leads to the improvement of tribological behavior.
基金financial support provided by Shahid Chamran University of Ahvaz, Iran
文摘Friction stir processing（FSP） was utilized to produce surface composites by incorporating nano-sized cerium oxide（CeO2） and silicon carbide（SiC） particles individually and in combined form into the Al5083 alloy matrix. The study signified the role of these reinforcements on microstructure and wear behavior of the resultant surface composite layers. The wear characteristics of the resultant mono and hybrid surface composite layers were investigated using a pin-on-disc wear tester at room temperature. The microstructural observations of FSPed regions and the worn out surfaces were performed by optical and scanning electron microscopy. Considerable grain refinement and uniform distribution of reinforcement particles were achieved inside the nugget zone. All the composite samples showed higher hardness and wear resistance compared to the base metal. Among the composite samples, the hybrid composite（Al5083/CeO2/SiC） revealed the highest wear resistance and the lowest friction coefficient, whereas the Al5083/SiC composite exhibited the highest hardness, i.e., 1.5 times as hard as that of the Al5083 base metal. The enhancement in wear behavior of the hybrid composites was attributed to the solid lubrication effect provided by CeO2 particles. The predominant wear mechanism was identified as severe adhesive in non-composite samples, which changed to abrasive wear and delamination in the presence of reinforcing particles.
