In order to remove hydrogen and inclusions from A356 alloy melt, a low melting point glass flux, JDN Ⅱ, was developed. The results indicated that JDN Ⅱ flux has distinct effect of purification and protection on A356...In order to remove hydrogen and inclusions from A356 alloy melt, a low melting point glass flux, JDN Ⅱ, was developed. The results indicated that JDN Ⅱ flux has distinct effect of purification and protection on A356 alloy melt. When the dosage of the flux was 3%, the content of hydrogen in A356 melt was only 2.6?mL/kg at 857?℃ and 0.7?mL/kg even at 750?℃. In the meantime, the mechanical properties of the alloy increase greatly with the covering of 3% JDN Ⅱ flux. Compared with no flux, the tensile strength of A356 alloy increases by 9.42% and the elongation increases by 22%. The purification mechanism of JDN Ⅱ glass flux was discussed too.展开更多
Rapid solidification of binary Cu-22%Sn peritectic alloys and Cu-5%Sn-5%Ni-5%Ag quaternary alloys was accomplished by glass fluxing, drop tube and melt spinning methods. The undercooled, by glass fluxing method, Cu-22...Rapid solidification of binary Cu-22%Sn peritectic alloys and Cu-5%Sn-5%Ni-5%Ag quaternary alloys was accomplished by glass fluxing, drop tube and melt spinning methods. The undercooled, by glass fluxing method, Cu-22%Sn peritectic alloy was composed of a（Cu） and δ（Cu41Snll） phases. If rapidly solidified in a drop tube, the alloy phase constitution changed from α（Cu） and δ（Cu41Sn11） phases into a single supersaturated （Cu） phase with the reducing of droplet diameter, and the maximum solubility of Sn in （Cu） phase extended to 22%. The Cu-5%Sn-5%Ni-5%Ag quaternary alloy was composed of （Cu） and （Ag） phases under the containerless processing condition in a drop tube, and the solute microsegregation of （Cu） phase was obvious. When the Cu-5%Sn-5%Ni-5%Ag quaternary alloy was solidified by melt spinning method, microsegregation was suppressed and solute trapping occurred. The experimental results show that the microstructures of primary （Cu） phase in the two alloys transfer from coarse dendrites into equiaxed grains with the increase of cooling rate and undercooling, which is accompanied by the grain refinement effect.展开更多
文摘In order to remove hydrogen and inclusions from A356 alloy melt, a low melting point glass flux, JDN Ⅱ, was developed. The results indicated that JDN Ⅱ flux has distinct effect of purification and protection on A356 alloy melt. When the dosage of the flux was 3%, the content of hydrogen in A356 melt was only 2.6?mL/kg at 857?℃ and 0.7?mL/kg even at 750?℃. In the meantime, the mechanical properties of the alloy increase greatly with the covering of 3% JDN Ⅱ flux. Compared with no flux, the tensile strength of A356 alloy increases by 9.42% and the elongation increases by 22%. The purification mechanism of JDN Ⅱ glass flux was discussed too.
基金supported by the National Natural Science Foundation of China (Grant No. 50971105)the Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20106102120052)the NPU Foundation for Fundamental Research (Grant No. G9KY1021)
文摘Rapid solidification of binary Cu-22%Sn peritectic alloys and Cu-5%Sn-5%Ni-5%Ag quaternary alloys was accomplished by glass fluxing, drop tube and melt spinning methods. The undercooled, by glass fluxing method, Cu-22%Sn peritectic alloy was composed of a（Cu） and δ（Cu41Snll） phases. If rapidly solidified in a drop tube, the alloy phase constitution changed from α（Cu） and δ（Cu41Sn11） phases into a single supersaturated （Cu） phase with the reducing of droplet diameter, and the maximum solubility of Sn in （Cu） phase extended to 22%. The Cu-5%Sn-5%Ni-5%Ag quaternary alloy was composed of （Cu） and （Ag） phases under the containerless processing condition in a drop tube, and the solute microsegregation of （Cu） phase was obvious. When the Cu-5%Sn-5%Ni-5%Ag quaternary alloy was solidified by melt spinning method, microsegregation was suppressed and solute trapping occurred. The experimental results show that the microstructures of primary （Cu） phase in the two alloys transfer from coarse dendrites into equiaxed grains with the increase of cooling rate and undercooling, which is accompanied by the grain refinement effect.
