Forming mechanism of refined granular crystalline of Cu_7oNi_30 alloy by undercooled solidification  

作　　者：郭学锋 刘峰 杨根仓 邢建东 

机构地区：[1]State Key laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an 710072, China [2]College of Materials Science and Engineering, Xi an University of Technology, Xi an 710048, China [3]School of Mechanical Engineering, Xi an Jiaotong University, Xi an 710049, China

出　　处：《Progress in Natural Science:Materials International》2000年第12期59-67,共9页自然科学进展·国际材料（英文版）

基　　金：Projects supported by the National Natural Science Foundation of China (Grant No. 59871041) and Natural Science Foundation of Shaanxi Province (Grant No. 98C13).

摘　　要：Both glass fluxing and cyclic, superheating techniques were adopted to effectively undercool the Cu70-Ni10 alloy in vacuum. Within the undercooling range of 21 K to 270 K, the microstruoture evolution of the alloy was investigated. When the melt was undercooled to △T】△T3(210 K) , the grain refinement took place abruptly. Based on the observation of the solidified microstructure, the microchemical-analysis and the calculated results with HCT model, it is found that the secondary grain refinement mechanism consists of two stages. The dendrite is, firstly, broken into fragments owing to the stress caused by uneven shrinking during rapid solidification, then the fragments, under the driving foree of surface and strain energies, merge through the migration of boundaries, i. e. recrystallizalion, thus leading to the formation of secondary granular-crystalline.Both glass fluxing and cyclic, superheating techniques were adopted to effectively undercool the Cu70-Ni10 alloy in vacuum. Within the undercooling range of 21 K to 270 K, the microstruoture evolution of the alloy was investigated. When the melt was undercooled to △T>△T3(210 K) , the grain refinement took place abruptly. Based on the observation of the solidified microstructure, the microchemical-analysis and the calculated results with HCT model, it is found that the secondary grain refinement mechanism consists of two stages. The dendrite is, firstly, broken into fragments owing to the stress caused by uneven shrinking during rapid solidification, then the fragments, under the driving foree of surface and strain energies, merge through the migration of boundaries, i. e. recrystallizalion, thus leading to the formation of secondary granular-crystalline.

关 键 词：UNDERCOOLING Cu70Ni30 ALLOY DENDRITE breaking recrystallization. 

分 类 号：TG139[一般工业技术—材料科学与工程]