Non lubricated slide performance of functional grade copper matrix composite,fabricated using horizontal centrifuge cast technique was investigated using pin-on-disc tribo-tester.Rate of wear and friction coefficient ...Non lubricated slide performance of functional grade copper matrix composite,fabricated using horizontal centrifuge cast technique was investigated using pin-on-disc tribo-tester.Rate of wear and friction coefficient of the inner wall thickness of hollow cylindrical cast specimen was analyzed using Taguchi based L27 orthogonal array,where the percentage of graphite particles were observed higher.Variable process parameters those influenced the rate of wear directly or indirectly were:applied load(15,25 and 35 N),slide velocity(1.5,2.5 and 3.5 m/s)and slide distance(750,1500 and 2250 m).Rate of wear and friction coefficient showed a proportional dependency with applied load and slide distance,whereas showing a decline during intermediate slide velocity.Signal-to-Noise ratio predicted the minimal tribo-condition,on‘smaller-the-better’basis.Analysis of Variance technique quantified the influence of affecting parameters,along with their interactions.Regression analysis was utilized for the validation of the experimental data.Micrographs and scanning electron microscopy exhibited the wear mechanisms and mechanically mixed layer formation during worn surfaces analysis.展开更多
Functionally graded Al/B_4C, Al/Si C, Al/Al_2O_3 and Al/TiB_2 composites with constant 12%(mass fraction) of reinforcement were fabricated by centrifugal casting and hollow cylindrical components were obtained. Micros...Functionally graded Al/B_4C, Al/Si C, Al/Al_2O_3 and Al/TiB_2 composites with constant 12%(mass fraction) of reinforcement were fabricated by centrifugal casting and hollow cylindrical components were obtained. Microstructural characteristics were investigated at outer surface of all composites and segregation of reinforcement particles was observed. Graded property of the composites with different reinforcements was investigated through hardness and tensile measurements. Results revealed that the outer peripheries of all composites exhibit higher hardness except in Al/B_4C composite and the outer zones of all composites show higher tensile strength. Abrasive wear test was conducted on the outer peripheries of all composites and Al/TiB_2 composite exhibits less wear rate.展开更多
The main objective of this paper was to fabricate CuSnNi alloy and its composites reinforced with various contents of SiNparticles(5wt%, 10wt%, and 15wt%) and to investigate their dry sliding wear behavior using a pin...The main objective of this paper was to fabricate CuSnNi alloy and its composites reinforced with various contents of SiNparticles(5wt%, 10wt%, and 15wt%) and to investigate their dry sliding wear behavior using a pin-on-disk tribometer. Microstructural examinations of the specimens revealed a uniform dispersion of SiNparticles in the copper matrix. Wear experiments were performed for all combinations of parameters, such as load(10, 20, and 30 N), sliding distance(500, 1000, and 1500 m), and sliding velocity(1, 2, and 3 m/s), for the alloy and the composites. The results revealed that wear rate increased with increasing load and increasing sliding distance, whereas the wear rate decreased and then increased with increasing sliding velocity. The primary wear mechanism encountered at low loads was mild adhesive wear, whereas that at high loads was severe delamination wear. An oxide layer was formed at low velocities, whereas a combination of shear and plastic deformation occurred at high velocities. The mechanism at short sliding distances was ploughing action of SiNparticles, which act as protrusions; by contrast, at long sliding distances, direct metal–metal contact occurred. Among the investigated samples, the Cu/10wt% SiNcomposite exhibited the best wear resistance at a load of 10 N, a velocity of 2 m/s, and a sliding distance of 500 m.展开更多
Aluminium hybrid functionally graded metal matrix composites(FGMMCs),meet growing demands for supreme tribo-mechanical performance in automotive and aviation industry.This research experimentally compares the influenc...Aluminium hybrid functionally graded metal matrix composites(FGMMCs),meet growing demands for supreme tribo-mechanical performance in automotive and aviation industry.This research experimentally compares the influence of carbide ceramics(B_(4)C,SiC,TiC)as reinforcements,in improving reciprocating tribology performance and mechanical strength of A333 hybrid composites against alloy.Hollow cylindrical samples of A333/6 wt%B_(4)C/4 wt%TiC and A333/6 wt%B_(4)C/4 wt%SiC hybrid FGMMCs were developed using horizontal centrifugal casting.Metallography analysis on both composites revealed increasing ceramic gradient distribution towards outer composite wall.Particle rich zone of A333/B_(4)C/SiC hybrid FGMMC showed maximum micro-hardness(198.9 HV)and tensile strength(267.9 MPa).Elemental mapping confirmed effective distribution of ceramics and detected elemental composition of both composites.Particle rich layer of A333/B_(4)C/SiC hybrid FGMMC exhibited improved wear resistance in comparison with all three layers of A333/B_(4)C/TiC hybrid FGMMC and alloy.Third-body abrasion and tribo-chemical wear were the predominant mechanisms revealed for both composites during worn surface analysis.展开更多
The ability to perform against extreme corrosion environments in stainless steel depreciates under challenging conditions in industrial applications.This can be resolved by employing surface modification techniques to...The ability to perform against extreme corrosion environments in stainless steel depreciates under challenging conditions in industrial applications.This can be resolved by employing surface modification techniques to modify the surface with the required characteristics.The present study investigates the outcomes of friction stir processing of SS304 with CoCrFeCuTi high entropy alloy(HEA)as reinforcement and the property enhancements post-annealing.The synthesized CoCrFeCuTi HEA exhibited irregular fragments with 17μm mean particle size and body centred cubic(BCC)phase.The microstructure of the processed surface revealed ultra-refined grains with a uniform distribution of HEA filler.The microstructures of the samples annealed at 400℃,550℃,700℃and 850℃for 2 h also showed significant grain growth and grain refinements.The processed sample with HEA reinforcement annealed at 700℃exhibited enhanced microhardness and tensile strength by 63%and 0.88 times than that of the processed sample with HEA pre-annealing.The subsequent electrochemical corrosion test displayed better corrosion resistance for the HEA-processed and annealed sample.Hot corrosion tests at 900℃showcased excellent resistance for the HEA processed and annealed samples by 14.92%,12.75%,and 14.83%against the samples pre-annealed under three different salt mixtures,and the corroded surface was analyzed.展开更多
文摘Non lubricated slide performance of functional grade copper matrix composite,fabricated using horizontal centrifuge cast technique was investigated using pin-on-disc tribo-tester.Rate of wear and friction coefficient of the inner wall thickness of hollow cylindrical cast specimen was analyzed using Taguchi based L27 orthogonal array,where the percentage of graphite particles were observed higher.Variable process parameters those influenced the rate of wear directly or indirectly were:applied load(15,25 and 35 N),slide velocity(1.5,2.5 and 3.5 m/s)and slide distance(750,1500 and 2250 m).Rate of wear and friction coefficient showed a proportional dependency with applied load and slide distance,whereas showing a decline during intermediate slide velocity.Signal-to-Noise ratio predicted the minimal tribo-condition,on‘smaller-the-better’basis.Analysis of Variance technique quantified the influence of affecting parameters,along with their interactions.Regression analysis was utilized for the validation of the experimental data.Micrographs and scanning electron microscopy exhibited the wear mechanisms and mechanically mixed layer formation during worn surfaces analysis.
基金Department of Science and Technology (India) for the financial support (Grant No.SR/S3/MERC/0116/2012)
文摘Functionally graded Al/B_4C, Al/Si C, Al/Al_2O_3 and Al/TiB_2 composites with constant 12%(mass fraction) of reinforcement were fabricated by centrifugal casting and hollow cylindrical components were obtained. Microstructural characteristics were investigated at outer surface of all composites and segregation of reinforcement particles was observed. Graded property of the composites with different reinforcements was investigated through hardness and tensile measurements. Results revealed that the outer peripheries of all composites exhibit higher hardness except in Al/B_4C composite and the outer zones of all composites show higher tensile strength. Abrasive wear test was conducted on the outer peripheries of all composites and Al/TiB_2 composite exhibits less wear rate.
文摘The main objective of this paper was to fabricate CuSnNi alloy and its composites reinforced with various contents of SiNparticles(5wt%, 10wt%, and 15wt%) and to investigate their dry sliding wear behavior using a pin-on-disk tribometer. Microstructural examinations of the specimens revealed a uniform dispersion of SiNparticles in the copper matrix. Wear experiments were performed for all combinations of parameters, such as load(10, 20, and 30 N), sliding distance(500, 1000, and 1500 m), and sliding velocity(1, 2, and 3 m/s), for the alloy and the composites. The results revealed that wear rate increased with increasing load and increasing sliding distance, whereas the wear rate decreased and then increased with increasing sliding velocity. The primary wear mechanism encountered at low loads was mild adhesive wear, whereas that at high loads was severe delamination wear. An oxide layer was formed at low velocities, whereas a combination of shear and plastic deformation occurred at high velocities. The mechanism at short sliding distances was ploughing action of SiNparticles, which act as protrusions; by contrast, at long sliding distances, direct metal–metal contact occurred. Among the investigated samples, the Cu/10wt% SiNcomposite exhibited the best wear resistance at a load of 10 N, a velocity of 2 m/s, and a sliding distance of 500 m.
文摘Aluminium hybrid functionally graded metal matrix composites(FGMMCs),meet growing demands for supreme tribo-mechanical performance in automotive and aviation industry.This research experimentally compares the influence of carbide ceramics(B_(4)C,SiC,TiC)as reinforcements,in improving reciprocating tribology performance and mechanical strength of A333 hybrid composites against alloy.Hollow cylindrical samples of A333/6 wt%B_(4)C/4 wt%TiC and A333/6 wt%B_(4)C/4 wt%SiC hybrid FGMMCs were developed using horizontal centrifugal casting.Metallography analysis on both composites revealed increasing ceramic gradient distribution towards outer composite wall.Particle rich zone of A333/B_(4)C/SiC hybrid FGMMC showed maximum micro-hardness(198.9 HV)and tensile strength(267.9 MPa).Elemental mapping confirmed effective distribution of ceramics and detected elemental composition of both composites.Particle rich layer of A333/B_(4)C/SiC hybrid FGMMC exhibited improved wear resistance in comparison with all three layers of A333/B_(4)C/TiC hybrid FGMMC and alloy.Third-body abrasion and tribo-chemical wear were the predominant mechanisms revealed for both composites during worn surface analysis.
文摘The ability to perform against extreme corrosion environments in stainless steel depreciates under challenging conditions in industrial applications.This can be resolved by employing surface modification techniques to modify the surface with the required characteristics.The present study investigates the outcomes of friction stir processing of SS304 with CoCrFeCuTi high entropy alloy(HEA)as reinforcement and the property enhancements post-annealing.The synthesized CoCrFeCuTi HEA exhibited irregular fragments with 17μm mean particle size and body centred cubic(BCC)phase.The microstructure of the processed surface revealed ultra-refined grains with a uniform distribution of HEA filler.The microstructures of the samples annealed at 400℃,550℃,700℃and 850℃for 2 h also showed significant grain growth and grain refinements.The processed sample with HEA reinforcement annealed at 700℃exhibited enhanced microhardness and tensile strength by 63%and 0.88 times than that of the processed sample with HEA pre-annealing.The subsequent electrochemical corrosion test displayed better corrosion resistance for the HEA-processed and annealed sample.Hot corrosion tests at 900℃showcased excellent resistance for the HEA processed and annealed samples by 14.92%,12.75%,and 14.83%against the samples pre-annealed under three different salt mixtures,and the corroded surface was analyzed.
