Magnesium alloy reinforced with 8% TiC(mass fraction) is in-situ synthesized using remelting and dilution technique. Damping capacity of AZ91 alloy and magnesium matrix composites was examined using Mark IV dynamic me...Magnesium alloy reinforced with 8% TiC(mass fraction) is in-situ synthesized using remelting and dilution technique. Damping capacity of AZ91 alloy and magnesium matrix composites was examined using Mark IV dynamic mechanical thermal analyzer. The results reveal that the damping capacity of materials is independent of frequency, but dependent on strain. Damping capacity of materials increase when testing strain enhances, and there is strain peak at damping-strain curve of materials. There are two temperature peaks at damping-temperature curve of magnesium matrix composites under 140℃ and 250℃ respectively. The damping mechanism is explained by dislocation motion, interface slip and grain boundary slip.展开更多
Metal matrix composite coating Ni-Fe/SiC was prepared on an iron-based substrate bythermal spraying combined with laser cladding,using SiC particulates as the reinforcing agent.The micro-structures of the coatings for...Metal matrix composite coating Ni-Fe/SiC was prepared on an iron-based substrate bythermal spraying combined with laser cladding,using SiC particulates as the reinforcing agent.The micro-structures of the coatings formed at different thermal spraying and laser cladding conditions were character-ized by means of X-ray diffraction and electron probe microanalysis.The thermal oxidation properties of themixed powders composed of different content of SiC particulates and relevant Ni-based alloy as the balancewere examined using differential scanning calorimetry.The hardness profile of the thermal sprayed and lasercladding coatings was investigated as well.It was found that SiO2particulates were generated and dissolvedand dispersed during the melting and solidification of the laser cladding process,which was ascribed to theoxidation of the dispersed SiC particulates.The micro-hardness depth profile of the target laser claddingcomposite coating was characterized by gradient distribution,which could be related to the gradient distribu-tion of the hard SiC and SiO2particulates in the dendrites and interdendrites of the cladding layer.Both SiCand SiO2particulates contributed to greatly increasing the microhardness and mechanical properties of the ti-tled laser cladding composite coatings.展开更多
Addition of reinforcement such as TiC, SiC, Al2O3, TiO2, TiN, etc. to Aluminium matrix for enhancing the mechanical properties has been a well established fact. In-situ method of reinforcement of the Aluminium matrix ...Addition of reinforcement such as TiC, SiC, Al2O3, TiO2, TiN, etc. to Aluminium matrix for enhancing the mechanical properties has been a well established fact. In-situ method of reinforcement of the Aluminium matrix with ceramic phase like Titanium Carbide (TiC) is well preferred over the Ex-situ method. In the present investigation, Al-Cu alloy (series of 2014 Aluminium alloy) was used as matrix and reinforced with TiC using In-situ process. The Metal Matrix Composite (MMC) material, Al-4.5%Cu/10%TiC developed exhibited higher yield strength, ultimate strength and hardness as compared to Al-4.5%Cu alloy. Percentage increase in yield and ultimate tensile strengths were reported to be about 15% and 24% respectively whereas Vickers hardness increased by about 35%. The higher values in hardness indicated that the TiC particles contributed to the increase of hardness of matrix. Fractured surface of the tensile specimen of the composite material indicated presence of dimpled surface, indicating thereby a ductile type of fracture. During the fabrication of composite, reaction products such as Al3Ti, Al2Cu and Al3C4 were identified with various morphologies and sizes in metal matrix.展开更多
文摘Magnesium alloy reinforced with 8% TiC(mass fraction) is in-situ synthesized using remelting and dilution technique. Damping capacity of AZ91 alloy and magnesium matrix composites was examined using Mark IV dynamic mechanical thermal analyzer. The results reveal that the damping capacity of materials is independent of frequency, but dependent on strain. Damping capacity of materials increase when testing strain enhances, and there is strain peak at damping-strain curve of materials. There are two temperature peaks at damping-temperature curve of magnesium matrix composites under 140℃ and 250℃ respectively. The damping mechanism is explained by dislocation motion, interface slip and grain boundary slip.
文摘Metal matrix composite coating Ni-Fe/SiC was prepared on an iron-based substrate bythermal spraying combined with laser cladding,using SiC particulates as the reinforcing agent.The micro-structures of the coatings formed at different thermal spraying and laser cladding conditions were character-ized by means of X-ray diffraction and electron probe microanalysis.The thermal oxidation properties of themixed powders composed of different content of SiC particulates and relevant Ni-based alloy as the balancewere examined using differential scanning calorimetry.The hardness profile of the thermal sprayed and lasercladding coatings was investigated as well.It was found that SiO2particulates were generated and dissolvedand dispersed during the melting and solidification of the laser cladding process,which was ascribed to theoxidation of the dispersed SiC particulates.The micro-hardness depth profile of the target laser claddingcomposite coating was characterized by gradient distribution,which could be related to the gradient distribu-tion of the hard SiC and SiO2particulates in the dendrites and interdendrites of the cladding layer.Both SiCand SiO2particulates contributed to greatly increasing the microhardness and mechanical properties of the ti-tled laser cladding composite coatings.
文摘Addition of reinforcement such as TiC, SiC, Al2O3, TiO2, TiN, etc. to Aluminium matrix for enhancing the mechanical properties has been a well established fact. In-situ method of reinforcement of the Aluminium matrix with ceramic phase like Titanium Carbide (TiC) is well preferred over the Ex-situ method. In the present investigation, Al-Cu alloy (series of 2014 Aluminium alloy) was used as matrix and reinforced with TiC using In-situ process. The Metal Matrix Composite (MMC) material, Al-4.5%Cu/10%TiC developed exhibited higher yield strength, ultimate strength and hardness as compared to Al-4.5%Cu alloy. Percentage increase in yield and ultimate tensile strengths were reported to be about 15% and 24% respectively whereas Vickers hardness increased by about 35%. The higher values in hardness indicated that the TiC particles contributed to the increase of hardness of matrix. Fractured surface of the tensile specimen of the composite material indicated presence of dimpled surface, indicating thereby a ductile type of fracture. During the fabrication of composite, reaction products such as Al3Ti, Al2Cu and Al3C4 were identified with various morphologies and sizes in metal matrix.
