A quenching and partitioning(Q&P) process was applied to vanadium carbide particle(VCp)-reinforced Fe-matrix composites(VC-Fe-MCs) to obtain a multiphase microstructure comprising VC, V8 C7, M3 C, α-Fe, and γ-Fe...A quenching and partitioning(Q&P) process was applied to vanadium carbide particle(VCp)-reinforced Fe-matrix composites(VC-Fe-MCs) to obtain a multiphase microstructure comprising VC, V8 C7, M3 C, α-Fe, and γ-Fe. The effects of the austenitizing temperature and the quenching temperature on the microstructure, mechanical properties, and wear resistance of the VC-Fe-MCs were studied. The results show that the size of the carbide became coarse and that the shape of some particles began to transform from diffused graininess into a chrysanthemum-shaped structure with increasing austenitizing temperature. The microhardness decreased with increasing austenitizing temperature but substantially increased after wear testing compared with the microhardness before wear testing; the microhardness values improved by 20.0% ± 2.5%. Retained austenite enhanced the impact toughness and promoted the transformation-induced plasticity(TRIP) effect to improve wear resistance under certain load conditions.展开更多
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
Three different groups of ceramic powders for the thermal-swayed coating were firstly prepared using sintering and ball milling. Then, these powders were separately deposited on three stainless steel substrates, follo...Three different groups of ceramic powders for the thermal-swayed coating were firstly prepared using sintering and ball milling. Then, these powders were separately deposited on three stainless steel substrates, followed by individual corrosion resistance examination. Microstructural characterization showed that the levels of micro-void and micro-crack at the bonding interface （between coating and substrate） depended on the proportions of different ceramic particles. Meanwhile, a significantly enhanced corrosion resistance was reproducibly observed in one group of as-coated samples that have the optimal combination of given ceramic powders. Furthermore, the mechanism of corresponding enhanced corrosion resistance was discussed. It was found that the optimal ceramic powders for the present thermal-sprayed coating should contain 30.2 wt% SiO2, 54 wt% Cr2O3, 6.8 wt% Al2O3, 4.8 wt% CaO and 1.8 wt% TiO2. The corrosion velocities of such samples in the 3.5 vol.% HCl, 15 wt% NaOH and 5 wt% NaCl solutions were 3.74, 2.98 and 0.50 g h-1 m-2 for 168, 336 and 336 h, respectively.展开更多
基金funded by Open Research Fund of State Key Laboratory of Precision Manufacturing for Extreme Service Performance, Central South University, China (No. Kfkt2020-01)Hunan Provincial Natural Science Foundation, China (No. 2021JJ40774)the Project of State Key Laboratory of High Performance Complex Manufacturing, Central South University, China (No. ZZYJKT2021-01)。
基金financially supported by the National Natural Science Foundation of China(Nos.51475480 and U1637601)the Research Funding from the State Key Laboratory of High-Performance Complex Manufacturing(No.ZZYJKT2017-01)+1 种基金Innovation Platform and Talent Plan of Hunan Province(No.2016RS2015)the Project of Innovation Driven Plan in Central South University(No.2015CX002)
文摘A quenching and partitioning(Q&P) process was applied to vanadium carbide particle(VCp)-reinforced Fe-matrix composites(VC-Fe-MCs) to obtain a multiphase microstructure comprising VC, V8 C7, M3 C, α-Fe, and γ-Fe. The effects of the austenitizing temperature and the quenching temperature on the microstructure, mechanical properties, and wear resistance of the VC-Fe-MCs were studied. The results show that the size of the carbide became coarse and that the shape of some particles began to transform from diffused graininess into a chrysanthemum-shaped structure with increasing austenitizing temperature. The microhardness decreased with increasing austenitizing temperature but substantially increased after wear testing compared with the microhardness before wear testing; the microhardness values improved by 20.0% ± 2.5%. Retained austenite enhanced the impact toughness and promoted the transformation-induced plasticity(TRIP) effect to improve wear resistance under certain load conditions.
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Three different groups of ceramic powders for the thermal-swayed coating were firstly prepared using sintering and ball milling. Then, these powders were separately deposited on three stainless steel substrates, followed by individual corrosion resistance examination. Microstructural characterization showed that the levels of micro-void and micro-crack at the bonding interface （between coating and substrate） depended on the proportions of different ceramic particles. Meanwhile, a significantly enhanced corrosion resistance was reproducibly observed in one group of as-coated samples that have the optimal combination of given ceramic powders. Furthermore, the mechanism of corresponding enhanced corrosion resistance was discussed. It was found that the optimal ceramic powders for the present thermal-sprayed coating should contain 30.2 wt% SiO2, 54 wt% Cr2O3, 6.8 wt% Al2O3, 4.8 wt% CaO and 1.8 wt% TiO2. The corrosion velocities of such samples in the 3.5 vol.% HCl, 15 wt% NaOH and 5 wt% NaCl solutions were 3.74, 2.98 and 0.50 g h-1 m-2 for 168, 336 and 336 h, respectively.
