Cu/Ti2AlC composites were fabricated by vacuum hot-pressing technique. Phase composition was analyzed by XRD and morphology of fracture was observed by SEM. Physical performance such as density, resistivity, hardness ...Cu/Ti2AlC composites were fabricated by vacuum hot-pressing technique. Phase composition was analyzed by XRD and morphology of fracture was observed by SEM. Physical performance such as density, resistivity, hardness and friction coefficient with different volume fraction of Cu/Ti2AlC composites were studied. When the content of Ti2AlC increased from 10% to 70%, the relative density reduced from 99.38% to 90.56% and the resistivity increased significantly. Hardness reached the maximum value when Ti2AlC was at 60% and friction coefficient declined with the increasing of Ti2AlC. Cu/Ti2AlC composites, showing good conductivity properties and friction performance. Oxidation resistance enhanced obviously with the content of Ti2AlC increasing. Cu-60%Ti2AlC sample possessed optimum thermal shock resistance, and no cracking was found at 600 ℃ cycled for 10 times and 900 ℃ cycled for 1 time.展开更多
The microstructure and the electrical, thermal, friction, and mechanical properties of Cu/Ti_2AlC fabricated by hot-pressing at 900 ℃ for 1 h were investigated in the present work. Microstructural observations have s...The microstructure and the electrical, thermal, friction, and mechanical properties of Cu/Ti_2AlC fabricated by hot-pressing at 900 ℃ for 1 h were investigated in the present work. Microstructural observations have shown that the plate-like Ti_2AlC grains distribute irregularly in the network of Cu grains, and well-structured, crack-free bonds between the layers. With the increase in the content of Ti_2AlC from layer A to layer D, the electrical resistivity increases from 1.381×10^（-7）Ω·m to 1.918 ×10^（-7）Ω·m, the hardness increases from about 980.27 MPa to about 2196.01 MPa, and the friction coefficient from above 0.20 reduces to about 0.15. Oxidation rate increases with the increases of temperature. Exfoliation was obviously observed on the surface of oxidation layer A. The surface of layer D was still intact and the spalling and other defects were not found. The mass decreases in the acid solution, and increases in the alkaline solution. The largest corrosion rate is found in 6.5% HNO_3 or 4% Na OH solution.展开更多
Ti2AlN/TiN functionally graded materials（FGM） were successfully fabricated by vacuum hotpressing. Bulk density of the sintered samples was measured by Archimedes principle. The sample sintered at 1 300 ℃ for 2h has...Ti2AlN/TiN functionally graded materials（FGM） were successfully fabricated by vacuum hotpressing. Bulk density of the sintered samples was measured by Archimedes principle. The sample sintered at 1 300 ℃ for 2h has the maximum final density and lowest open porosity. SEM coupled with EDS was utilized to investigate the phase composition and microstructure, and well-formed boundary was found between the layers. The microhardness tests suggest that Vickers’ hardness of Ti2AlN/TiN FGM increases monotonically with the volume fraction content of TiN increases. Corrosion results are that the corrosion resistance of Ti2AlN/TiN FGM is much better than that of Ti2AlN in acid, but quite the opposite in alkali. Constant temperature oxidation study shows that the oxidation kinetics of Ti2AlN/TiN FGM at 900 °C follows the parabolic law closely.展开更多
基金Funded by Hubei Province Natural Science Foundation(No.2012FFB00608)the Youth Science and Technology Morning Program of Wuhan(No.201150431129)+1 种基金the Youth Science and Technology Program of Hubei Province Education Department(No.20121407)National Natural Science Foundation of China(No.51273059)
文摘Cu/Ti2AlC composites were fabricated by vacuum hot-pressing technique. Phase composition was analyzed by XRD and morphology of fracture was observed by SEM. Physical performance such as density, resistivity, hardness and friction coefficient with different volume fraction of Cu/Ti2AlC composites were studied. When the content of Ti2AlC increased from 10% to 70%, the relative density reduced from 99.38% to 90.56% and the resistivity increased significantly. Hardness reached the maximum value when Ti2AlC was at 60% and friction coefficient declined with the increasing of Ti2AlC. Cu/Ti2AlC composites, showing good conductivity properties and friction performance. Oxidation resistance enhanced obviously with the content of Ti2AlC increasing. Cu-60%Ti2AlC sample possessed optimum thermal shock resistance, and no cracking was found at 600 ℃ cycled for 10 times and 900 ℃ cycled for 1 time.
基金The Open Foundation of Hubei Provincial Key Laboratory of Green Material for Light Industry(No.(2013)2-general project-9)the Key Project of Education Department of Hubei(No.D20131406)the National Natural Science Foundation of China(No.51302073)
文摘The microstructure and the electrical, thermal, friction, and mechanical properties of Cu/Ti_2AlC fabricated by hot-pressing at 900 ℃ for 1 h were investigated in the present work. Microstructural observations have shown that the plate-like Ti_2AlC grains distribute irregularly in the network of Cu grains, and well-structured, crack-free bonds between the layers. With the increase in the content of Ti_2AlC from layer A to layer D, the electrical resistivity increases from 1.381×10^（-7）Ω·m to 1.918 ×10^（-7）Ω·m, the hardness increases from about 980.27 MPa to about 2196.01 MPa, and the friction coefficient from above 0.20 reduces to about 0.15. Oxidation rate increases with the increases of temperature. Exfoliation was obviously observed on the surface of oxidation layer A. The surface of layer D was still intact and the spalling and other defects were not found. The mass decreases in the acid solution, and increases in the alkaline solution. The largest corrosion rate is found in 6.5% HNO_3 or 4% Na OH solution.
基金Funded by the Natural Science Foundation of Hubei Province(No.2012FFB00608)the Education Department of Hubei Province Key Project(No.D20131406)the National Natural Science Foundation of China(No.51302073)
文摘Ti2AlN/TiN functionally graded materials（FGM） were successfully fabricated by vacuum hotpressing. Bulk density of the sintered samples was measured by Archimedes principle. The sample sintered at 1 300 ℃ for 2h has the maximum final density and lowest open porosity. SEM coupled with EDS was utilized to investigate the phase composition and microstructure, and well-formed boundary was found between the layers. The microhardness tests suggest that Vickers’ hardness of Ti2AlN/TiN FGM increases monotonically with the volume fraction content of TiN increases. Corrosion results are that the corrosion resistance of Ti2AlN/TiN FGM is much better than that of Ti2AlN in acid, but quite the opposite in alkali. Constant temperature oxidation study shows that the oxidation kinetics of Ti2AlN/TiN FGM at 900 °C follows the parabolic law closely.
