Using Al Mg and Al Mg Y alloys as raw materials and nitrogen as gas reactants, AlN powders and composite AlN powders by in situ synthesis method were prepared. AlN lumps prepared by the nitriding of Al Mg and Al ...Using Al Mg and Al Mg Y alloys as raw materials and nitrogen as gas reactants, AlN powders and composite AlN powders by in situ synthesis method were prepared. AlN lumps prepared by the nitriding of Al Mg and Al Mg Y alloys have porous microstructure, which is favorable for pulverization. They have high purity, containing 1.23%(mass fraction) oxygen impurity, and consisted of AlN single phase. The average particle size of AlN powders is 6.78 μm. Composite AlN powders consist of AlN phases and rare earth oxide Y 2O 3 phase. The distribution of particle size of AlN powders shows two peaks. In view of packing factor, AlN powders with such size distribution can easily be sintered to high density.展开更多
In this study, magnesium matrix composites reinforced with different loading of AlN particles were fabricated by the powder metallurgy technique. The microstructure, bending strength and fracture behavior of the resul...In this study, magnesium matrix composites reinforced with different loading of AlN particles were fabricated by the powder metallurgy technique. The microstructure, bending strength and fracture behavior of the resulting Mg-Al/Al N composites were investigated. It showed that the 5 wt% AlN reinforcements led to the highest densification and bending strength. The total strengthening effect of AlN particles was predicted by considering the contributions of CTE mismatch between the matrix and the particles,load bearing and Hall-Petch mechanism. The results revealed that the increase of dislocation density,the change of Mg17Al12 phase morphology, and the effective load transfer were the major strengthening contributors to the composites. The fracture of the composites altered from plastic to brittle mode with increasing reinforcement content. The regions of clustered particles in the composites were easy to be damaged under external load, and the fracture occurred mainly along grain boundaries.展开更多
文摘Using Al Mg and Al Mg Y alloys as raw materials and nitrogen as gas reactants, AlN powders and composite AlN powders by in situ synthesis method were prepared. AlN lumps prepared by the nitriding of Al Mg and Al Mg Y alloys have porous microstructure, which is favorable for pulverization. They have high purity, containing 1.23%(mass fraction) oxygen impurity, and consisted of AlN single phase. The average particle size of AlN powders is 6.78 μm. Composite AlN powders consist of AlN phases and rare earth oxide Y 2O 3 phase. The distribution of particle size of AlN powders shows two peaks. In view of packing factor, AlN powders with such size distribution can easily be sintered to high density.
基金financially supported by the State Key Laboratory for Mechanical Behavior of Materials (No. 20151712)
文摘In this study, magnesium matrix composites reinforced with different loading of AlN particles were fabricated by the powder metallurgy technique. The microstructure, bending strength and fracture behavior of the resulting Mg-Al/Al N composites were investigated. It showed that the 5 wt% AlN reinforcements led to the highest densification and bending strength. The total strengthening effect of AlN particles was predicted by considering the contributions of CTE mismatch between the matrix and the particles,load bearing and Hall-Petch mechanism. The results revealed that the increase of dislocation density,the change of Mg17Al12 phase morphology, and the effective load transfer were the major strengthening contributors to the composites. The fracture of the composites altered from plastic to brittle mode with increasing reinforcement content. The regions of clustered particles in the composites were easy to be damaged under external load, and the fracture occurred mainly along grain boundaries.
