Nucleation sites of α-Al grains after addition of an Al-Ti-B master alloy into pure aluminium have been investigated using EPMA. The results show that either TiAl3 or boride particales can nucleate α-Al grains. But ...Nucleation sites of α-Al grains after addition of an Al-Ti-B master alloy into pure aluminium have been investigated using EPMA. The results show that either TiAl3 or boride particales can nucleate α-Al grains. But the number of TiAl3 nucleants is reduced with the holding time prolonged and the boride-nuclei are increasing gradually. Based on these results, a new refining method, adding molten Al-Ti-B into commercially pure aluminium, which has a quicker and better refining efficiency is presented.展开更多
It has been reported that the element scandium (Sc) is the most effective modificator which can significantly refine the grain size,prohibit recrystallization process and increase the strength.Adding trace of Sc in 70...It has been reported that the element scandium (Sc) is the most effective modificator which can significantly refine the grain size,prohibit recrystallization process and increase the strength.Adding trace of Sc in 7000 series aluminum alloys is considered to be an effective way to modify its microstructure and promote mechanical properties.In order to study the effect of Sc element on ascast microstructure of Al-Zn-Mg-Cu-Zr alloy,ingots containing different amounts of Sc were prepared by ferrous-mold cast.Microstructures were characterized by means of differential scanning calorimeter (DSC),X-ray diffraction (XRD),optical microscope (OM) and scanning electrical microscope (SEM).The results indicate that when the Sc level exceeds a critical concentration,A13(Sc,Zr) primary phase would form in the melt and act as an efficient nucleant,resulting in very refined grain and an equiaxed grain structure.Sc element reduces the number of eutectic phases formed during solidification,coupled with an increase in the concentration of major alloying elements retained in the solute.This behavior suggests possible benefits in improving the integrated properties of terminal products.展开更多
文摘Nucleation sites of α-Al grains after addition of an Al-Ti-B master alloy into pure aluminium have been investigated using EPMA. The results show that either TiAl3 or boride particales can nucleate α-Al grains. But the number of TiAl3 nucleants is reduced with the holding time prolonged and the boride-nuclei are increasing gradually. Based on these results, a new refining method, adding molten Al-Ti-B into commercially pure aluminium, which has a quicker and better refining efficiency is presented.
基金financially supported by the National Key Research and Development Program of China (No. 2016YFB0300903)
文摘It has been reported that the element scandium (Sc) is the most effective modificator which can significantly refine the grain size,prohibit recrystallization process and increase the strength.Adding trace of Sc in 7000 series aluminum alloys is considered to be an effective way to modify its microstructure and promote mechanical properties.In order to study the effect of Sc element on ascast microstructure of Al-Zn-Mg-Cu-Zr alloy,ingots containing different amounts of Sc were prepared by ferrous-mold cast.Microstructures were characterized by means of differential scanning calorimeter (DSC),X-ray diffraction (XRD),optical microscope (OM) and scanning electrical microscope (SEM).The results indicate that when the Sc level exceeds a critical concentration,A13(Sc,Zr) primary phase would form in the melt and act as an efficient nucleant,resulting in very refined grain and an equiaxed grain structure.Sc element reduces the number of eutectic phases formed during solidification,coupled with an increase in the concentration of major alloying elements retained in the solute.This behavior suggests possible benefits in improving the integrated properties of terminal products.
