The effects of Ti/N ratio on the number densities of nano particles,the size of the prior austenite grain(PAG)and the toughness of the heat-affected zone(HAZ)of Mg-deoxidized steels were studied after high heat input ...The effects of Ti/N ratio on the number densities of nano particles,the size of the prior austenite grain(PAG)and the toughness of the heat-affected zone(HAZ)of Mg-deoxidized steels were studied after high heat input welding of 400 kJ/cm.With increasing the Ti/N ratio from 2.7 to 5.7,the cuboid nano-sized particles are formed,and their number density increases.The area fractions of ductile intragranular acicular ferrites(IAFs)have the highest value and the area fractions of brittle microstructures of ferrite side plates and upper bainites have the lowest value in TN30 steel.With the Ti/N ratio of about 3.0,the HAZ of steel plate has the best low-temperature toughness.With increasing the Ti/N ratio from 2.7 to 5.7,the PAG sizes after the high-temperature laser scanning confocal microscopy observation decrease linearly with increasing the number densities of nano-sized particles.The PAG size of TN30 steel is between 100 and 150μm,which is conducive to the nucleation of IAFs.展开更多
Cr_(2)O_(3)was used as grain inhibitor in Ti(C,N)-based cermets with vacuum sintering.The microstructure and mechanical and tribological properties of cermets with Cr_(2)O_(3)and Cr_(3)C_(2)were investigated.The resul...Cr_(2)O_(3)was used as grain inhibitor in Ti(C,N)-based cermets with vacuum sintering.The microstructure and mechanical and tribological properties of cermets with Cr_(2)O_(3)and Cr_(3)C_(2)were investigated.The results show that adding Cr_(2)O_(3)promotes a gray core/gray rim structure formation and finer size of Ti(C,N)hard phase.Compared with the cermet with an equal Cr_(3)C_(2)addition,the cermet with 0.6 wt.%Cr_(2)O_(3)exhibits 16.5%higher transverse rupture strength.This enhancement is likely due to the smaller lattice misfit at the core/rim interface and more uniform Cr distribution in the binder.Additionally,at room temperature(25℃)and 800℃,Cr_(2)O_(3)-containing cermets demonstrate lower coefficients of friction and volume wear ratios than Cr_(3)C_(2)-containing cermets,with the wear ratio difference reaching an order of magnitude.Scanning electron microscopy and X-ray photoelectron spectroscopy results further confirm more oxidation wear in Cr_(2)O_(3)-containing cermets than in Cr_(3)C_(2)-containing cermets.展开更多
基金financially supported by the National Natural Science Foundation of China(52474361).
文摘The effects of Ti/N ratio on the number densities of nano particles,the size of the prior austenite grain(PAG)and the toughness of the heat-affected zone(HAZ)of Mg-deoxidized steels were studied after high heat input welding of 400 kJ/cm.With increasing the Ti/N ratio from 2.7 to 5.7,the cuboid nano-sized particles are formed,and their number density increases.The area fractions of ductile intragranular acicular ferrites(IAFs)have the highest value and the area fractions of brittle microstructures of ferrite side plates and upper bainites have the lowest value in TN30 steel.With the Ti/N ratio of about 3.0,the HAZ of steel plate has the best low-temperature toughness.With increasing the Ti/N ratio from 2.7 to 5.7,the PAG sizes after the high-temperature laser scanning confocal microscopy observation decrease linearly with increasing the number densities of nano-sized particles.The PAG size of TN30 steel is between 100 and 150μm,which is conducive to the nucleation of IAFs.
基金Natural Science Foundation of Ningxia,China(No.2023AAC03284)Fundamental Research Funds for the Central Universities Research Project of North Minzu University,China(No.2022XYZCL04)+1 种基金Project of Key Laboratory of Powders and Advanced CeramicsCo-founded by Ningxia and the State Ethnic Affairs Commission,China(No.2103)。
文摘Cr_(2)O_(3)was used as grain inhibitor in Ti(C,N)-based cermets with vacuum sintering.The microstructure and mechanical and tribological properties of cermets with Cr_(2)O_(3)and Cr_(3)C_(2)were investigated.The results show that adding Cr_(2)O_(3)promotes a gray core/gray rim structure formation and finer size of Ti(C,N)hard phase.Compared with the cermet with an equal Cr_(3)C_(2)addition,the cermet with 0.6 wt.%Cr_(2)O_(3)exhibits 16.5%higher transverse rupture strength.This enhancement is likely due to the smaller lattice misfit at the core/rim interface and more uniform Cr distribution in the binder.Additionally,at room temperature(25℃)and 800℃,Cr_(2)O_(3)-containing cermets demonstrate lower coefficients of friction and volume wear ratios than Cr_(3)C_(2)-containing cermets,with the wear ratio difference reaching an order of magnitude.Scanning electron microscopy and X-ray photoelectron spectroscopy results further confirm more oxidation wear in Cr_(2)O_(3)-containing cermets than in Cr_(3)C_(2)-containing cermets.
