Pearlitic ductile irons(PDIs)are used in transportation and nuclear energy industries.In heavy loading situation,the service life of PDI is affected by numerous tribo aspects.In this study,surface of the PDI is alloye...Pearlitic ductile irons(PDIs)are used in transportation and nuclear energy industries.In heavy loading situation,the service life of PDI is affected by numerous tribo aspects.In this study,surface of the PDI is alloyed with WC-12%Co powder using a high power fibre laser.The wear properties of the base material and laser alloying samples were investigated by tribometer with various parameters,i.e.,temperature,load and sliding speed.Based on experimental test,the load has maximum percentage of contribution and followed by sliding speed and working temperature.The optimized tribological parameters by Grey relational analysis(GRA)were established and those values are closely matched with predicted values.Besides,base material and laser alloying surfaces were examined through Vickers hardness machine,scanning electron microscopy(SEM)and roughness tester.The laser altered specimen shows no defects and improves the wear properties than substrates.The identified optimal tribological parameters are load of 30 N,speed of 0.5 m/s and working temperature of 300℃,and load of 30 N,speed of 0.5 m/s and working temperature of 200℃ for base metal and laser alloying samples,respectively.展开更多
Stainless steel (SS) 410 is widely used in many components of nuclear reactors due to its good corrosion resistance and high strength. However, wear is a major issue of these components due to its continuous sliding. ...Stainless steel (SS) 410 is widely used in many components of nuclear reactors due to its good corrosion resistance and high strength. However, wear is a major issue of these components due to its continuous sliding. SS 420 and Colmonoy 5 particles were deposited over SS 410 substrate by laser cladding process. Then, X-ray diffraction was used to find the phases present after cladding process. Further, coating morphologies were analysed by scanning electron microscopy (SEM) twinned with energy-dispersive spectroscopy. The obtained morphology indicates the hard laves phase present in the Colmonoy 5 cladding surface and needle-like structure in SS 420 cladding surface. Then, Vickers microhardness test was carried out in order to study the hardness and load-carrying capacity of the cladding specimen. Among those, Colmonoy 5 cladding specimen provide higher hardness due to the presence of laves phase formation. Then, the dry sliding wear study was conducted to calculate the mass loss after 2500 m of sliding. The combined effect of hardness and laves phase formation were reflected in dry sliding wear study analysis of the specimens. Then, to study the wear mechanism and roughness, worn surface morphologies were captured using SEM and white light interferometer, respectively.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Pearlitic ductile irons(PDIs)are used in transportation and nuclear energy industries.In heavy loading situation,the service life of PDI is affected by numerous tribo aspects.In this study,surface of the PDI is alloyed with WC-12%Co powder using a high power fibre laser.The wear properties of the base material and laser alloying samples were investigated by tribometer with various parameters,i.e.,temperature,load and sliding speed.Based on experimental test,the load has maximum percentage of contribution and followed by sliding speed and working temperature.The optimized tribological parameters by Grey relational analysis(GRA)were established and those values are closely matched with predicted values.Besides,base material and laser alloying surfaces were examined through Vickers hardness machine,scanning electron microscopy(SEM)and roughness tester.The laser altered specimen shows no defects and improves the wear properties than substrates.The identified optimal tribological parameters are load of 30 N,speed of 0.5 m/s and working temperature of 300℃,and load of 30 N,speed of 0.5 m/s and working temperature of 200℃ for base metal and laser alloying samples,respectively.
基金Ministry of Science and Technology(MOST),Taiwan,China,for providing financial support to carry out this research work.
文摘Stainless steel (SS) 410 is widely used in many components of nuclear reactors due to its good corrosion resistance and high strength. However, wear is a major issue of these components due to its continuous sliding. SS 420 and Colmonoy 5 particles were deposited over SS 410 substrate by laser cladding process. Then, X-ray diffraction was used to find the phases present after cladding process. Further, coating morphologies were analysed by scanning electron microscopy (SEM) twinned with energy-dispersive spectroscopy. The obtained morphology indicates the hard laves phase present in the Colmonoy 5 cladding surface and needle-like structure in SS 420 cladding surface. Then, Vickers microhardness test was carried out in order to study the hardness and load-carrying capacity of the cladding specimen. Among those, Colmonoy 5 cladding specimen provide higher hardness due to the presence of laves phase formation. Then, the dry sliding wear study was conducted to calculate the mass loss after 2500 m of sliding. The combined effect of hardness and laves phase formation were reflected in dry sliding wear study analysis of the specimens. Then, to study the wear mechanism and roughness, worn surface morphologies were captured using SEM and white light interferometer, respectively.
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.
