The effect of vanadium carbide（VC） on the grain size of commercial pure aluminum was experimentally investigated by varying the content of VC, the holding time, and casting temperature. The refining efficiencies of ...The effect of vanadium carbide（VC） on the grain size of commercial pure aluminum was experimentally investigated by varying the content of VC, the holding time, and casting temperature. The refining efficiencies of VC and Al5Ti1 B were also compared. The refined samples of commercial pure aluminum were examined using optical microscopy, scanning electron microscopy（SEM） and energy-dispersive spectroscopy（EDS）. The results suggest that VC is a good refiner of commercial pure aluminum. The addition of only 0.3wt% VC can decrease the grain size of aluminum to 102 μm, whereas the casting temperature and holding time have little effect on the grain size. The refining efficiency of VC is better than that of Al5Ti1 B. The VC particles in molten aluminum act as nuclei and the grain refinement of aluminum alloys by VC particles is achieved via heterogeneous nucleation.展开更多
Ultrafine austenite grains with average size of 2μm were successfully obtained by combining thermo-mechanical control process followed by reheating in a vanadium microalloyed steel.The mixed microstructure transforme...Ultrafine austenite grains with average size of 2μm were successfully obtained by combining thermo-mechanical control process followed by reheating in a vanadium microalloyed steel.The mixed microstructure transformed from pancaked austenite formed during controlled rolling has a higher density of high angle boundaries,compared to that transformed from equiaxial austenite.It contributes to increasing nucleation density of austenite grain during the reheating process.A certain volume fraction of undissolved nano-sized（Ti,V）C particles,which are formed during the controlled rolling process and/or the reheating process,effectively inhibit austenite grain growth and consequently refine austenite grain size significantly.The critical grain size of austenite calculated by Gladman model agrees well with the experimental result.展开更多
基金financially supported by the Department of Science and Technology of Sichuan Province (Nos. 2015KJT0081-2015G, 2015GZ0052, and 13CGZH0200)
文摘The effect of vanadium carbide（VC） on the grain size of commercial pure aluminum was experimentally investigated by varying the content of VC, the holding time, and casting temperature. The refining efficiencies of VC and Al5Ti1 B were also compared. The refined samples of commercial pure aluminum were examined using optical microscopy, scanning electron microscopy（SEM） and energy-dispersive spectroscopy（EDS）. The results suggest that VC is a good refiner of commercial pure aluminum. The addition of only 0.3wt% VC can decrease the grain size of aluminum to 102 μm, whereas the casting temperature and holding time have little effect on the grain size. The refining efficiency of VC is better than that of Al5Ti1 B. The VC particles in molten aluminum act as nuclei and the grain refinement of aluminum alloys by VC particles is achieved via heterogeneous nucleation.
基金Sponsored by National Basic Research Program of China(2010CB630805)
文摘Ultrafine austenite grains with average size of 2μm were successfully obtained by combining thermo-mechanical control process followed by reheating in a vanadium microalloyed steel.The mixed microstructure transformed from pancaked austenite formed during controlled rolling has a higher density of high angle boundaries,compared to that transformed from equiaxial austenite.It contributes to increasing nucleation density of austenite grain during the reheating process.A certain volume fraction of undissolved nano-sized（Ti,V）C particles,which are formed during the controlled rolling process and/or the reheating process,effectively inhibit austenite grain growth and consequently refine austenite grain size significantly.The critical grain size of austenite calculated by Gladman model agrees well with the experimental result.
