The aim of this study was to produce bulk nanocrystalline Al/Al12（Fe,V）3Si alloys by mechanical alloying （MA） and subsequent hot pressing （HP） of elemental powders. A nanostructured Al-based solid solution was f...The aim of this study was to produce bulk nanocrystalline Al/Al12（Fe,V）3Si alloys by mechanical alloying （MA） and subsequent hot pressing （HP） of elemental powders. A nanostructured Al-based solid solution was formed by MA of elemental powders for 60 h. After HP of the as-milled powders at 550℃ for 20 min, the Al12（Fe,V）3Si phase was precipitated in a nanocrystalline Al matrix. Scanning electron microscopy （SEM） images of the bulk samples represented a homogeneous and uniform microstructure that was superior to those previously obtained by rapid solidification-powder metallurgy （RS-PM）. Nanostructured Al-8.5Fe-1.3V-1.7Si and Al-11.6Fe-1.3V-2.3Si alloys ex-hibited high HV hardness values of～205 and～254, respectively, which are significantly higher than those reported for the RS-PM counter-parts.展开更多
The effect of solution temperature and cooling rate on microstructure and mechanical properties of laser solid forming （LSF） Ti-6A1-4V alloy is investigated. The samples are solutions treated at 900, 950, and 1000 ...The effect of solution temperature and cooling rate on microstructure and mechanical properties of laser solid forming （LSF） Ti-6A1-4V alloy is investigated. The samples are solutions treated at 900, 950, and 1000 ℃, followed by water quenching, air cooling, and furnace cooling, respectively. It is found that the cooling rate of solution treatment hasα more important effect on the microstructure in comparison with the solution temperature. The martensite α formed during water quenching results in the higher hardness and tensile strength but lower ductility of samples. With decreasing the cooling rate and increasing the solution temperature, the width of primary α laths increases, and the aspect ratio and volume fraction decrease, which make the hardness and tensile strength decrease and the ductility increase.展开更多
文摘The aim of this study was to produce bulk nanocrystalline Al/Al12（Fe,V）3Si alloys by mechanical alloying （MA） and subsequent hot pressing （HP） of elemental powders. A nanostructured Al-based solid solution was formed by MA of elemental powders for 60 h. After HP of the as-milled powders at 550℃ for 20 min, the Al12（Fe,V）3Si phase was precipitated in a nanocrystalline Al matrix. Scanning electron microscopy （SEM） images of the bulk samples represented a homogeneous and uniform microstructure that was superior to those previously obtained by rapid solidification-powder metallurgy （RS-PM）. Nanostructured Al-8.5Fe-1.3V-1.7Si and Al-11.6Fe-1.3V-2.3Si alloys ex-hibited high HV hardness values of～205 and～254, respectively, which are significantly higher than those reported for the RS-PM counter-parts.
基金supported by the Program for New Century Excellent Talents in University of China (No.NCET-06-0879)the National Natural Science Foundation of China (No.50331010)+2 种基金the National "863" Program of China (No.2006AA03Z0449)the National "973" Program of China (No.2007CB613800)the Programme of Introducing Talents of Discipline to Universities(No.08040)
文摘The effect of solution temperature and cooling rate on microstructure and mechanical properties of laser solid forming （LSF） Ti-6A1-4V alloy is investigated. The samples are solutions treated at 900, 950, and 1000 ℃, followed by water quenching, air cooling, and furnace cooling, respectively. It is found that the cooling rate of solution treatment hasα more important effect on the microstructure in comparison with the solution temperature. The martensite α formed during water quenching results in the higher hardness and tensile strength but lower ductility of samples. With decreasing the cooling rate and increasing the solution temperature, the width of primary α laths increases, and the aspect ratio and volume fraction decrease, which make the hardness and tensile strength decrease and the ductility increase.
