A ceramic coating containing Cu element was prepared on Ti6Al4V alloy using micro-arc oxidation（MAO）technology.After copper ions were added to the electrolyte solution of aluminate salt,the anode voltage in MAO proc...A ceramic coating containing Cu element was prepared on Ti6Al4V alloy using micro-arc oxidation（MAO）technology.After copper ions were added to the electrolyte solution of aluminate salt,the anode voltage in MAO process reduces,and the micropore size on the surface of the ceramic coating is more uniform.The crystalline phases of the ceramic coatings prepared in the electrolyte solutions with and without copper ions are mainly Ti element,rutile TiO_2,and anatase TiO_2.The addition of copper ions to the electrolyte solution makes rutile TiO_2 content decrease but promotes the formation of Al_2TiO_5 phase.Energy spectrum test results confirm that by adding copper ions to the electrolyte solution,the ceramic coating formed in the process of MAO contains copper element.展开更多
Zn-Fe and Y-modified Zn-Fe coatings were prepared on 42 CrMo steel through pack cementation processes at 370,390 and 410℃ for 4 h.Y modification was achieved through the co-deposition of Zn and Y_(2)O_(3).The effects...Zn-Fe and Y-modified Zn-Fe coatings were prepared on 42 CrMo steel through pack cementation processes at 370,390 and 410℃ for 4 h.Y modification was achieved through the co-deposition of Zn and Y_(2)O_(3).The effects of Y modification on microstructure,formation and corrosion behavior of the Zn-Fe coating were investigated.The coating thickness increased with an increase in temperature.The Y-modified Zn-Fe coating was thicker than the plain Zn-Fe coating.Both the Zn-Fe coating and Y-modified Zn-Fe coating showed single-layered structures,but the overall microstructure was improved by Y modification.The activation energies for Zn-Fe coating and Y-modified Zn-Fe coating were 113.15 and80.65 kJ·mol^(-1),respectively.The Zn-Fe coating consisted of FeZn_(13) and Fe11Zn40 phases.The effects of Y modification on the corrosion behavior of the Zn-Fe coating were evaluated through an immersion test and polarization measurements.The results showed that the corrosion resistance was improved by Y modification.展开更多
The cenospheres/AZ91D composites were fabricated by melt stir method. The phases, microstructure and tensile fracture morphology of the composites were analyzed using XRD, Olympus metallurgical microscopy and SEM meth...The cenospheres/AZ91D composites were fabricated by melt stir method. The phases, microstructure and tensile fracture morphology of the composites were analyzed using XRD, Olympus metallurgical microscopy and SEM methods. The thermal expansion coefficient(CTE) and tensile properties were measured. The results showed that the cenospheres distribute uniformly in the Mg alloy matrix and refine the matrix microstructure. Mg2 Si and MgO were found in addition to α-Mg and β-Mg17Al12 phases using XRD. The CTE of the composites reduced after the cenospheres are added. The yield strength of the composites increases significantly with an increase in the mass fraction and a decrease in the size of the cenospheres. The tensile strength of the composites achieves maximum when the mass fraction of cenospheres is 9wt.% and the size of cenospheres is 80 μm. The fracture mechanism of the composites is cleavage fracture.展开更多
The fly ash cenosphere/AZ91D composites were successfully prepared and isothermally heat-treated at different tem- peratures for different time. The effects of semi-solid isothermal heat treatment on the microstructur...The fly ash cenosphere/AZ91D composites were successfully prepared and isothermally heat-treated at different tem- peratures for different time. The effects of semi-solid isothermal heat treatment on the microstructures and damping capacities of fly ash cenosphere/AZ91D composites were investigated. With the increase in isothermal temperature or holding time, the small liquid droplets within grains increased in size but decreased in quantity. The average size and shape factor of Mg2Si particles increased with the rise of isothermal temperature. The damping capacities of the composites were improved by isothermal heat treatment. At room temperature, the composites after heat treatment at 520 and 550 ℃ had a higher damping capacity due to interface damping when the strain amplitude was lower than about 8.8 × 10^-5, and the composite after heat treatment at 580 ℃ had a better damping capacity because of the dislocation damping under the condition of high strain amplitude. The damping capacities of the composites increased with the rise of the test temper- ature, and the damping mechanisms varied depending on different test temperatures. The interface damping played an important role when the test temperature was below about 100 ℃, and the dislocation damping and grain boundary damping took effect with the rise of test temperature.展开更多
基金financially supported by Shandong Provincial Natural Science Foundation of China(No.ZR2011EMM015)the Doctoral Program of Higher Education of the Ministry of Education of the Special Research Fund(No.20110133110003)China University of Petroleum(Huadong)Graduate Innovative Funding Projects(No.CX-1236)
文摘A ceramic coating containing Cu element was prepared on Ti6Al4V alloy using micro-arc oxidation（MAO）technology.After copper ions were added to the electrolyte solution of aluminate salt,the anode voltage in MAO process reduces,and the micropore size on the surface of the ceramic coating is more uniform.The crystalline phases of the ceramic coatings prepared in the electrolyte solutions with and without copper ions are mainly Ti element,rutile TiO_2,and anatase TiO_2.The addition of copper ions to the electrolyte solution makes rutile TiO_2 content decrease but promotes the formation of Al_2TiO_5 phase.Energy spectrum test results confirm that by adding copper ions to the electrolyte solution,the ceramic coating formed in the process of MAO contains copper element.
基金financially supported by the Natural Science Foundation of Shandong Province of China(No.ZR2017LEM004)the Open Fund of Key Laboratory of Oil&Gas Equipment,Ministry of Education(Southwest Petroleum University)(No.OGE201702-07)the Fundamental Research Funds for the Central Universities(Nos.16CX06020A and 18CX02091A)。
文摘Zn-Fe and Y-modified Zn-Fe coatings were prepared on 42 CrMo steel through pack cementation processes at 370,390 and 410℃ for 4 h.Y modification was achieved through the co-deposition of Zn and Y_(2)O_(3).The effects of Y modification on microstructure,formation and corrosion behavior of the Zn-Fe coating were investigated.The coating thickness increased with an increase in temperature.The Y-modified Zn-Fe coating was thicker than the plain Zn-Fe coating.Both the Zn-Fe coating and Y-modified Zn-Fe coating showed single-layered structures,but the overall microstructure was improved by Y modification.The activation energies for Zn-Fe coating and Y-modified Zn-Fe coating were 113.15 and80.65 kJ·mol^(-1),respectively.The Zn-Fe coating consisted of FeZn_(13) and Fe11Zn40 phases.The effects of Y modification on the corrosion behavior of the Zn-Fe coating were evaluated through an immersion test and polarization measurements.The results showed that the corrosion resistance was improved by Y modification.
基金financially supported by the Natural Science Funds of Heilongjiang Province(No.E201467)Project for Science and Technology of Jiamusi University(No.Ljz2012-04)Project for Science and Technology of Education Department of Heilongjiang Province(No.12511535)
文摘The cenospheres/AZ91D composites were fabricated by melt stir method. The phases, microstructure and tensile fracture morphology of the composites were analyzed using XRD, Olympus metallurgical microscopy and SEM methods. The thermal expansion coefficient(CTE) and tensile properties were measured. The results showed that the cenospheres distribute uniformly in the Mg alloy matrix and refine the matrix microstructure. Mg2 Si and MgO were found in addition to α-Mg and β-Mg17Al12 phases using XRD. The CTE of the composites reduced after the cenospheres are added. The yield strength of the composites increases significantly with an increase in the mass fraction and a decrease in the size of the cenospheres. The tensile strength of the composites achieves maximum when the mass fraction of cenospheres is 9wt.% and the size of cenospheres is 80 μm. The fracture mechanism of the composites is cleavage fracture.
基金supported by the Open Fund (No.OGE201702-07) of Key Laboratory of Oil and Gas Equipment,Ministry of Education (Southwest Petroleum University)the Key Research and Development Project of Shandong Province (No.2016GGX102041)+1 种基金the Natural Science Foundation of Shandong Province (No.ZR2017LEM004)the Fundamental Research Funds for the Central Universities of China (No.18CX02091A)
文摘The fly ash cenosphere/AZ91D composites were successfully prepared and isothermally heat-treated at different tem- peratures for different time. The effects of semi-solid isothermal heat treatment on the microstructures and damping capacities of fly ash cenosphere/AZ91D composites were investigated. With the increase in isothermal temperature or holding time, the small liquid droplets within grains increased in size but decreased in quantity. The average size and shape factor of Mg2Si particles increased with the rise of isothermal temperature. The damping capacities of the composites were improved by isothermal heat treatment. At room temperature, the composites after heat treatment at 520 and 550 ℃ had a higher damping capacity due to interface damping when the strain amplitude was lower than about 8.8 × 10^-5, and the composite after heat treatment at 580 ℃ had a better damping capacity because of the dislocation damping under the condition of high strain amplitude. The damping capacities of the composites increased with the rise of the test temper- ature, and the damping mechanisms varied depending on different test temperatures. The interface damping played an important role when the test temperature was below about 100 ℃, and the dislocation damping and grain boundary damping took effect with the rise of test temperature.
