在高真空下 ,研究了净化剂B2 O3,79%SiO2 + 1 2 .5%B2 O3+ 2 .2 %Al2 O3+ 0 .6%CaO + 5.7%Na2 O(简写为Na Ca Al B Si)和 50 %Na Ca Al B Si+ 50 %Na2 B7O4对Cu50 Ni50 合金熔体在循环过热过程中的过冷度及其稳定性的影响。结果表明 ,B2...在高真空下 ,研究了净化剂B2 O3,79%SiO2 + 1 2 .5%B2 O3+ 2 .2 %Al2 O3+ 0 .6%CaO + 5.7%Na2 O(简写为Na Ca Al B Si)和 50 %Na Ca Al B Si+ 50 %Na2 B7O4对Cu50 Ni50 合金熔体在循环过热过程中的过冷度及其稳定性的影响。结果表明 ,B2 O3的净化过程为纯物理净化 ,合金熔体在循环过热过程中不能获得稳定的深过冷 ;Na Ca Al B Si玻璃的净化过程为物理 -化学复合净化 ,但由于该净化剂粘度大 ,在循环过热的冷却过程中因发生合金熔体与净化剂分离 ,使合金熔体表面氧化 ,导致合金熔体同样不能获得稳定深过冷 ;50 %Na Ca Al B Si+ 50 %Na2 B7O4玻璃的净化过程为物理 -化学复合净化 ,该净化剂粘度适中 ,合金熔体在循环过热过程中可以获得稳定深过冷。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
文摘在高真空下 ,研究了净化剂B2 O3,79%SiO2 + 1 2 .5%B2 O3+ 2 .2 %Al2 O3+ 0 .6%CaO + 5.7%Na2 O(简写为Na Ca Al B Si)和 50 %Na Ca Al B Si+ 50 %Na2 B7O4对Cu50 Ni50 合金熔体在循环过热过程中的过冷度及其稳定性的影响。结果表明 ,B2 O3的净化过程为纯物理净化 ,合金熔体在循环过热过程中不能获得稳定的深过冷 ;Na Ca Al B Si玻璃的净化过程为物理 -化学复合净化 ,但由于该净化剂粘度大 ,在循环过热的冷却过程中因发生合金熔体与净化剂分离 ,使合金熔体表面氧化 ,导致合金熔体同样不能获得稳定深过冷 ;50 %Na Ca Al B Si+ 50 %Na2 B7O4玻璃的净化过程为物理 -化学复合净化 ,该净化剂粘度适中 ,合金熔体在循环过热过程中可以获得稳定深过冷。
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.
