The effects of boron on electrical conductivity of aluminum and the action mechanism have been investigated. The results indicate that, by combining with the trace amounts of transition elements Ti, V and Zr to form t...The effects of boron on electrical conductivity of aluminum and the action mechanism have been investigated. The results indicate that, by combining with the trace amounts of transition elements Ti, V and Zr to form two kinds of insoluble borides, boron can significantly improve the electrical conductivity of commercial aluminum. One of the borides contains 54.42% B, 13.70% Al and 23.39%(mole fraction) transition elements (including Ti, V, Zr and Fe) and is in the form of fine particles. The other one, in hexagonal shape, contains 78.59% B, 14.97% Al and 2.56%(mole fraction) transition elements (including Ti, V and Fe). Neither Cr nor Mn is found in these borides. The conversion of some transition metal impurities from solid solution state to the boride precipitates form leads to a decrease in electrical resistivity, and this decrease constitutes 86.2% of that can be achieved by complete removal of transition element impurities from aluminum melts.展开更多
Effects of Ce addition on microstructure, castability （fluidity and hot tearing sensitivity）, mechanical properties and electric conductivity of commercial purity aluminum （CP-AI） were investigated through microst...Effects of Ce addition on microstructure, castability （fluidity and hot tearing sensitivity）, mechanical properties and electric conductivity of commercial purity aluminum （CP-AI） were investigated through microstructure observation and performance tests. Results show that adding Ce in a CP-AI can considerably refine the grains, and has an important influence on the amount, crystallographic forms, and distribution of secondary phases. Addition of Ce also has a large impact on the fluidity and hot tearing sensitivity （HTS） of the CP-AI. With the addition of Ce from 0.1wt.% to 0.5wt.%, the fluidity of CP-AI is first increased remarkably and then decreased, and the HTS has an opposite response. The best castability of the studied alloys appears to be at 0.2wt.%-0.3wt.% Ce addition. The remarkable improvement in castability is attributed to the considerable refinement of grain structure. Ce addition can also lead to a significant rise in electric conductivity. The maximum conductivity of the as-cast CP-Al is 59.7% IACS with an addition of 0.2wt.%Ce. The T7 heat treatment can further improves the conductivity to 60.7% IACS. The Ce-induced evolution of the secondary phases is believed to be the mechanism for it.展开更多
文摘The effects of boron on electrical conductivity of aluminum and the action mechanism have been investigated. The results indicate that, by combining with the trace amounts of transition elements Ti, V and Zr to form two kinds of insoluble borides, boron can significantly improve the electrical conductivity of commercial aluminum. One of the borides contains 54.42% B, 13.70% Al and 23.39%(mole fraction) transition elements (including Ti, V, Zr and Fe) and is in the form of fine particles. The other one, in hexagonal shape, contains 78.59% B, 14.97% Al and 2.56%(mole fraction) transition elements (including Ti, V and Fe). Neither Cr nor Mn is found in these borides. The conversion of some transition metal impurities from solid solution state to the boride precipitates form leads to a decrease in electrical resistivity, and this decrease constitutes 86.2% of that can be achieved by complete removal of transition element impurities from aluminum melts.
基金supported by GM Research Foundation under contract No.GB1279-NV
文摘Effects of Ce addition on microstructure, castability （fluidity and hot tearing sensitivity）, mechanical properties and electric conductivity of commercial purity aluminum （CP-AI） were investigated through microstructure observation and performance tests. Results show that adding Ce in a CP-AI can considerably refine the grains, and has an important influence on the amount, crystallographic forms, and distribution of secondary phases. Addition of Ce also has a large impact on the fluidity and hot tearing sensitivity （HTS） of the CP-AI. With the addition of Ce from 0.1wt.% to 0.5wt.%, the fluidity of CP-AI is first increased remarkably and then decreased, and the HTS has an opposite response. The best castability of the studied alloys appears to be at 0.2wt.%-0.3wt.% Ce addition. The remarkable improvement in castability is attributed to the considerable refinement of grain structure. Ce addition can also lead to a significant rise in electric conductivity. The maximum conductivity of the as-cast CP-Al is 59.7% IACS with an addition of 0.2wt.%Ce. The T7 heat treatment can further improves the conductivity to 60.7% IACS. The Ce-induced evolution of the secondary phases is believed to be the mechanism for it.
