摘要
采用熔融玻璃净化和循环过热相结合获得熔体深过冷的方法,使Cu34.15%Pb(质量分数)偏晶合金获得了最大204K的大过冷度。研究了CuPb偏晶合金凝固组织随过冷度的演化规律,探讨了深过冷下合金的凝固机制,发现合金在小过冷度(<147K)情况下只有一次再辉,而在大过冷度下(≥147K)有两次再辉现象。研究表明:合金在小过冷度下α(Cu)相和L2液相基本同时形核,而在大过冷度下则是富Pb的L2液相先形核,随后在更大的过冷度下α(Cu)相形核并开始凝固。不同过冷度下合金的凝固组织均由α(Cu)相和Pb相组成。随过冷度增大,α(Cu)枝晶细化,Pb相尺寸变小。在97～161K过冷度区间内,试样中有热裂出现。在174～204K的过冷度区间内,组织出现明显分层。
The microstructure evolution and solidification behavior of undercooled Cu-34.15wt% Pb monotectic alloy were studied by employing the method of molten glass purification combined with thermal cycling. By using this method, high undercoolings of Cu-34.15wt%Pb monotectic alloy up to 204 K were obtained. During solidification it was found that only once recalescence occurred for those melts with low undercoolings (2 forms almost at the same time for those alloys with low undercooling, whereas for those melts with high undercooling, L2 phase nucleates firstly and then α(Cu) nucleates and grows rapidly. It is found the microstructures are composed of α(Cu) and Pb for those solidified alloys under all undercoolings. In the undercooling range of 97 K and 161 K, hot-cracks are observed in the samples after solidification. Obvious gravity segregation and delaminations microstructure are found in the alloy obtained in undercooling range of 174 K and 204 K.
出处
《材料热处理学报》
EI
CAS
CSCD
北大核心
2005年第4期44-47,51,共5页
Transactions of Materials and Heat Treatment
基金
陕西省教育厅专项科研计划项目(03JK132)
陕西省自然科学研究计划项目(2003E1)
关键词
Cu—Pb偏晶合金
深过冷
再辉
凝固
Cooling
Lead alloys
Nucleation
Solidification
Thermal cycling
