The wear resistance of iron(Fe)-matrix materials could be improved through the in situ formation of vanadium carbide particles(VCp)with high hardness.However,brittleness and low impact toughness limit their applicatio...The wear resistance of iron(Fe)-matrix materials could be improved through the in situ formation of vanadium carbide particles(VCp)with high hardness.However,brittleness and low impact toughness limit their application in several industries due to addition of higher carbon content.Carbon-partitioning treatment plays an important role in tuning the microstructure and mechanical properties of in situ VCp-reinforced Fe-matrix composite.In this study,the influences of carbon-partitioning temperatures and times on the microstructure,mechanical properties,and wear resistance of in situ VCp-reinforced Fe-matrix composite were investigated.The experimental results indicated that a certain amount of retained austenite could be stabilized at room temperature through the carbon-partitioning treatment.Microhardness of in situ VCp-reinforced Fematrix composite under carbon-partitioning treatment could be decreased,but impact toughness was improved accordingly when wear resistance was enhanced.In addition,the enhancement of wear resistance could be attributed to transformation-induced plasticity(TRIP)effect,and phase transformation was caused fromγ-Fe(face-centered cubic structure,fcc)toα-Fe(body-centered cubic structure,bcc)under a certain load.展开更多
Effects of quenching temperature and cooling conditions(water cooling and 10%NaCl cooling)on microstructure and mechanical properties of a 0.2%Ti low alloy martensitic wear-resistant steel used for die casting ejector...Effects of quenching temperature and cooling conditions(water cooling and 10%NaCl cooling)on microstructure and mechanical properties of a 0.2%Ti low alloy martensitic wear-resistant steel used for die casting ejector plate were investigated.The results show that lath martensite can be obtained after austenitizing in the range of 860-980℃and then water cooling.With an increase in austenitizing temperature,the precipitate content gradually decreases.The precipitates are mainly composed of TiC and Ti4C2S2,and their total content is between 1.15wt.%and 1.64wt.%.The precipitate phase concentration by water-cooling is higher than that by10%NaCl cooling due to the lower cooling rate of water cooling.As the austeniting temperature increases,the hardness and tensile strength of both water cooled and 10%NaCl cooled steels firstly increase and then decrease.The experimental steel exhibits the best comprehensive mechanical properties after being austenitized at 900℃,cooled by 10%NaCl,and then tempered at 200℃.Its hardness,ultimate tensile strength,and wear rate reach551.4 HBW,1,438.2 MPa,and 0.48×10^(-2)mg·m^(-1),respectively.展开更多
The effect of deep cryogenic treatment on the microstructure, hardness, and wear behavior of D2 tool steel was studied by scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, X-ray diffracti...The effect of deep cryogenic treatment on the microstructure, hardness, and wear behavior of D2 tool steel was studied by scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, X-ray diffraction （XRD）, hardness test, pin-on-disk wear test, and the reciprocating pin-on-fiat wear test. The results show that deep cryogenic treatment eliminates retained austenite, makes a better carbide distribution, and increases the carbide content. Furthermore, some new nano-sized carbides form during the deep cryogenic treatment, thereby increasing the hardness and improving the wear behavior of the samples.展开更多
The distribution of residual austenite in the laser hardening laver on the gray cast iron and the change in the amount of residual austenite during sliding wearing have been investigated by X-ray diffractometer.The th...The distribution of residual austenite in the laser hardening laver on the gray cast iron and the change in the amount of residual austenite during sliding wearing have been investigated by X-ray diffractometer.The thin foils of the hardening layer worn down have been observed by electron microscopy.It was revealed that two types of martensite are strain-induced by slid- ing wearing under load of 1.72 MPa on the hardening layer of residual austenite.The strain induced martensite is profitable to improve the sliding wearing resistance.展开更多
基金financially supported by the China Postdoctoral Foundation (No. 2019M650339)Guangdong Basic and Applied Basic Research Foundation (No. 2019A1515011858)+3 种基金Hunan Provincial Natural Science Foundation, China (No. 2019JJ50807)the State Key Laboratory of High Performance Complex Manufacturing, China (No. ZZYJKT2017-01)the DGUT Innovation Center of Robotics and Intelligent Equipment of China (No. KCYCXPT2017006)the Key Laboratory of Robotics and Intelligent Equipment of Guangdong Regular Institutions of Higher Education, China (No. 2017KSYS009)
文摘The wear resistance of iron(Fe)-matrix materials could be improved through the in situ formation of vanadium carbide particles(VCp)with high hardness.However,brittleness and low impact toughness limit their application in several industries due to addition of higher carbon content.Carbon-partitioning treatment plays an important role in tuning the microstructure and mechanical properties of in situ VCp-reinforced Fe-matrix composite.In this study,the influences of carbon-partitioning temperatures and times on the microstructure,mechanical properties,and wear resistance of in situ VCp-reinforced Fe-matrix composite were investigated.The experimental results indicated that a certain amount of retained austenite could be stabilized at room temperature through the carbon-partitioning treatment.Microhardness of in situ VCp-reinforced Fematrix composite under carbon-partitioning treatment could be decreased,but impact toughness was improved accordingly when wear resistance was enhanced.In addition,the enhancement of wear resistance could be attributed to transformation-induced plasticity(TRIP)effect,and phase transformation was caused fromγ-Fe(face-centered cubic structure,fcc)toα-Fe(body-centered cubic structure,bcc)under a certain load.
文摘Effects of quenching temperature and cooling conditions(water cooling and 10%NaCl cooling)on microstructure and mechanical properties of a 0.2%Ti low alloy martensitic wear-resistant steel used for die casting ejector plate were investigated.The results show that lath martensite can be obtained after austenitizing in the range of 860-980℃and then water cooling.With an increase in austenitizing temperature,the precipitate content gradually decreases.The precipitates are mainly composed of TiC and Ti4C2S2,and their total content is between 1.15wt.%and 1.64wt.%.The precipitate phase concentration by water-cooling is higher than that by10%NaCl cooling due to the lower cooling rate of water cooling.As the austeniting temperature increases,the hardness and tensile strength of both water cooled and 10%NaCl cooled steels firstly increase and then decrease.The experimental steel exhibits the best comprehensive mechanical properties after being austenitized at 900℃,cooled by 10%NaCl,and then tempered at 200℃.Its hardness,ultimate tensile strength,and wear rate reach551.4 HBW,1,438.2 MPa,and 0.48×10^(-2)mg·m^(-1),respectively.
文摘The effect of deep cryogenic treatment on the microstructure, hardness, and wear behavior of D2 tool steel was studied by scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, X-ray diffraction （XRD）, hardness test, pin-on-disk wear test, and the reciprocating pin-on-fiat wear test. The results show that deep cryogenic treatment eliminates retained austenite, makes a better carbide distribution, and increases the carbide content. Furthermore, some new nano-sized carbides form during the deep cryogenic treatment, thereby increasing the hardness and improving the wear behavior of the samples.
文摘The distribution of residual austenite in the laser hardening laver on the gray cast iron and the change in the amount of residual austenite during sliding wearing have been investigated by X-ray diffractometer.The thin foils of the hardening layer worn down have been observed by electron microscopy.It was revealed that two types of martensite are strain-induced by slid- ing wearing under load of 1.72 MPa on the hardening layer of residual austenite.The strain induced martensite is profitable to improve the sliding wearing resistance.
