To improve the wear resistance and corrosion resistance of magnesium alloys, a 5 kW continuous wave CO2 laser was used to investigate the laser surface cladding on AZ31 B magnesium alloys with Al-Si/Al2O3-TiO2 composi...To improve the wear resistance and corrosion resistance of magnesium alloys, a 5 kW continuous wave CO2 laser was used to investigate the laser surface cladding on AZ31 B magnesium alloys with Al-Si/Al2O3-TiO2 composite powders. A detailed microstructure, chemical composition, and phase analysis of the composite coatings were studied by scanning electron microscopy （SEM）, energy dispersive spectroscopy （EDS）, and X-ray diffraction （XRD）. The laser cladding shows good metallurgical bonding with the substrate. The composite coatings are composed of Mgl7Al12, Al3Mg2, Mg2Si, Al2O3, and TiO2 phases. Compared to the average microhardness （50HV0.05） of the AZ3 1 B substrate, that of the composite coatings （230HV0.05） is improved significantly. The wear resistances of the surface layers were evaluated in detail. The results demonstrate that the wear resistances of the laser surface-modified samples are considerably improved compared to the substrate. It also show that the composite coatings exhibit better corrosion resistance than that of the substrate in 3.5wt% NaCI solution.展开更多
In-situ TiB_2/AZ31 composites were prepared by utilizing the SHS reaction of Al-Ti-B system in the molten magnesium,and the effects of external physical fields on the dispersion of TiB_2 particles were investigated.Th...In-situ TiB_2/AZ31 composites were prepared by utilizing the SHS reaction of Al-Ti-B system in the molten magnesium,and the effects of external physical fields on the dispersion of TiB_2 particles were investigated.The results show that high-energy ultrasonic vibration could effectively break up the particle clusters and make the TiB2 particles uniformly distributed in the melt of TiB_2/AZ31 composites.The compound field(high-energy ultrasonic field coupling with electromagnetic field)could not only distribute the TiB_2 particles into the matrix uniformly,but also make the grains of α-Mg free and uniform further than the ultrasonic field solo.The average grain size of as-cast TiB_2/AZ31 composites was reduced from 173μm to 94μm.展开更多
基金Funded by the national Natural Science Foundation of China (No. 51075293)the Foundation for Development of Science and Technology of Taiyuan University of Technology,China(No.K201014)
文摘To improve the wear resistance and corrosion resistance of magnesium alloys, a 5 kW continuous wave CO2 laser was used to investigate the laser surface cladding on AZ31 B magnesium alloys with Al-Si/Al2O3-TiO2 composite powders. A detailed microstructure, chemical composition, and phase analysis of the composite coatings were studied by scanning electron microscopy （SEM）, energy dispersive spectroscopy （EDS）, and X-ray diffraction （XRD）. The laser cladding shows good metallurgical bonding with the substrate. The composite coatings are composed of Mgl7Al12, Al3Mg2, Mg2Si, Al2O3, and TiO2 phases. Compared to the average microhardness （50HV0.05） of the AZ3 1 B substrate, that of the composite coatings （230HV0.05） is improved significantly. The wear resistances of the surface layers were evaluated in detail. The results demonstrate that the wear resistances of the laser surface-modified samples are considerably improved compared to the substrate. It also show that the composite coatings exhibit better corrosion resistance than that of the substrate in 3.5wt% NaCI solution.
基金Item Sponsored by National High Technology Research and Development Program of China[No.2009AA03Z525]Aviation Science Foundation of China[No.20095263005]
文摘In-situ TiB_2/AZ31 composites were prepared by utilizing the SHS reaction of Al-Ti-B system in the molten magnesium,and the effects of external physical fields on the dispersion of TiB_2 particles were investigated.The results show that high-energy ultrasonic vibration could effectively break up the particle clusters and make the TiB2 particles uniformly distributed in the melt of TiB_2/AZ31 composites.The compound field(high-energy ultrasonic field coupling with electromagnetic field)could not only distribute the TiB_2 particles into the matrix uniformly,but also make the grains of α-Mg free and uniform further than the ultrasonic field solo.The average grain size of as-cast TiB_2/AZ31 composites was reduced from 173μm to 94μm.
