The combined electromagnetic fields were achieved by the application of an alternating magnetic field and a stationary magnetic field and were used during direct chill(DC) casting process to control the microstructure...The combined electromagnetic fields were achieved by the application of an alternating magnetic field and a stationary magnetic field and were used during direct chill(DC) casting process to control the microstructure and macrosegregation of an Al-Zn-Mg-Cu alloy. Ingot microstructures were analyzed under an optical microscope(Leica DMR). The composition at different locations in the ingots was measured with inductively coupled plasma mass spectrometry(ICP) method. The results showed that the grain structure is transformed from dendrite to equiaxed structure and significantly refined with the application of combined electromagnetic fields. The uniformity of microstructure is also greatly improved. The combined electromagnetic fields show a significant effect on the distribution of elements. The negative macrosegregation in the centre area of the ingot is obviously reduced.展开更多
Degassing is very important for aluminum alloys especially for 7xxx series alloys.In the present study,a high shear technology was used to degas 7032 aluminum alloy in order to study its degassing efficiency.The exper...Degassing is very important for aluminum alloys especially for 7xxx series alloys.In the present study,a high shear technology was used to degas 7032 aluminum alloy in order to study its degassing efficiency.The experimental results showed that the high shear technology can significantly degas 7032 aluminum alloy.By applying intensive melt shearing and an Ar injection of 60 seconds,the density index,D_i,was reduced from13.25%to 0.28%and the hydrogen concentration was significantly reduced from 0.31 to 0.10 mL/100 g Al.Compared with the conventional rotary degassing,high shear technology showed a much higher degassing efficiency,achieving a lower concentration of hydrogen in a shorter time.The water simulation experiment was used to study the mechanism of the high degassing efficiency.The small bubble size and the uniform distribution of Ar bubbles with the application of high shear technology are believed to be the main cause for the high degassing efficiency.展开更多
基金supported by the National Natural Science Foundation of China(51374067)the Outstanding Young Scholars'Growth Plan in the Colleges and Universities of Liaoning Province(LJQ2014032)the National Basic Research Program of China(2012CB619506)
文摘The combined electromagnetic fields were achieved by the application of an alternating magnetic field and a stationary magnetic field and were used during direct chill(DC) casting process to control the microstructure and macrosegregation of an Al-Zn-Mg-Cu alloy. Ingot microstructures were analyzed under an optical microscope(Leica DMR). The composition at different locations in the ingots was measured with inductively coupled plasma mass spectrometry(ICP) method. The results showed that the grain structure is transformed from dendrite to equiaxed structure and significantly refined with the application of combined electromagnetic fields. The uniformity of microstructure is also greatly improved. The combined electromagnetic fields show a significant effect on the distribution of elements. The negative macrosegregation in the centre area of the ingot is obviously reduced.
基金financially supported by the National Natural Science Foundation of China(51104043 and 51374067)the Outstanding Young Scholars Growth Plan in the Colleges and Universities of Liaoning Province(LJQ2014032)the National Basic Research Program of China(2012CB619506)
文摘Degassing is very important for aluminum alloys especially for 7xxx series alloys.In the present study,a high shear technology was used to degas 7032 aluminum alloy in order to study its degassing efficiency.The experimental results showed that the high shear technology can significantly degas 7032 aluminum alloy.By applying intensive melt shearing and an Ar injection of 60 seconds,the density index,D_i,was reduced from13.25%to 0.28%and the hydrogen concentration was significantly reduced from 0.31 to 0.10 mL/100 g Al.Compared with the conventional rotary degassing,high shear technology showed a much higher degassing efficiency,achieving a lower concentration of hydrogen in a shorter time.The water simulation experiment was used to study the mechanism of the high degassing efficiency.The small bubble size and the uniform distribution of Ar bubbles with the application of high shear technology are believed to be the main cause for the high degassing efficiency.
