摘要
对Cu-10%Co-10%Fe(质量分数)亚稳液态组元不混溶合金开展了气体雾化快速凝固实验,制备了富Fe-Co相球形粒子均匀分布于基体Cu的复合粉末,建立了Cu-Co-Fe合金雾化液滴冷却过程中的温度场、浓度场和液-液相变动力学控制方程,研发了耦合合金热力学和相变动力学的模拟方法,模拟分析了Cu-10%Co-10%Fe合金雾化液滴的凝固组织形成过程.实验和模拟结果表明,在气体雾化快速凝固条件下,液-液相变过程中富Fe-Co相液滴Marangoni迁移和Ostwald熟化的影响很弱,粉末中心绝大部分区域内富Fe-Co相粒子的空间分布均匀.对于直径小于220 mm的Cu-10%Co-10%Fe合金粉末,富Fe-Co相粒子的平均半径Ra和数量密度N与雾化粉末直径d之间符合指数关系.
Cu-Co-Fe alloys have excellent properties such as high strength, high electrical conductivity and giant magneto resistance（GMR）. These alloys are promising candidates to be used as electric contactors, integrated circuit lead frame, wires cables, ferromagnetism materials. However, the manufacturing of Cu- Co- Fe alloys is extremely difficult due to the presence of metastable miscibility gap in the liquid state. The liquid-liquid decomposition generally leads to serious phase segregated microstructure during the conventional solidification process. Studies in recent years reveal that rapid solidification techniques can effectively suppress the liquid phase separation. In this work, rapid solidification experiment is carried out with Cu-10%Co-10%Fe（mass fraction） alloy by using the high pressure gas atomization technique. Powders having composite microstructure with the Fe- Co- rich particles homogeneously dispersing in the Cu matrix are obtained. A model is developed to describe the microstructure evolution in an atomized droplet of Cu-Co-Fe alloy during the liquid-liquid phase transformation. The microstructure formation is simulated by coupling the thermodynamic and kinetic calculations. The favorable agreements between the calculated and experimental results for the powders of different sizes indicate that the model describes the microstructure evolution in the atomized droplets of Cu-Co-Fe alloy well. The results demonstrate that the effect of the Marangoni migration and Ostwald coarsening of the Fe-Co-rich droplets are very week under the rapid cooling conditions of gas atomization. For Cu-10%Co-10%Fe powders with diameter less than 220 mm, the average radius Raand number density N of the Fe-Co-rich particles depend exponentially on the powder diameter d.
出处
《金属学报》
SCIE
EI
CAS
CSCD
北大核心
2015年第7期883-888,共6页
Acta Metallurgica Sinica
基金
国家自然科学基金项目51271185
51031003和51471173资助~~
关键词
Cu-Co-Fe合金
液相分离
快速凝固
建模及模拟
Cu-Co-Fe alloy
liquid phase decomposition
rapid solidification
modeling and simulation
