中文摘要：

通过气体雾化技术研究了Cu100-XFeX（X=15,20,30和40）合金的凝固行为.考虑少量相液滴形核、扩散长大、空间迁移、凝固界面与液滴间的相互作用以及体积分数等共同影响因素,建立了能描述该类合金凝固组织演变动力学模型.将数学模型与雾化液滴飞行过程中运动、传热和传质的控制方程相耦合,给出了数值求解方法,模拟计算了Cu基亚稳难混溶合金液-液相分离过程.结果表明：富Fe粒子的平均尺寸随着Fe含量的增加而增大;少量相液滴形核发生在基体熔体过饱和度峰值附近;随着冷却速度的增大,雾化液滴中少量相液滴的形核率增大,但平均半径减小;少量相液滴在Marangoni迁移和与固/液界面相互排斥共同作用下,向雾化液滴中心迁移,使雾化粉末最终形成壳型组织结构.

英文摘要：

The solidification behavior of Culoo-xFex（X = 15, 20, 30 and 40） alloys was investigated by gas atomization. Considering the common action of minority phase spheres＇ nucleation, diffusion growth, spatial movement and interaction between solidification interface and minority phase spheres, a model was developed to describe the kinetics of metastable liquid-liquid phase transformation and microstructure evolution in the metastable immiscible alloys with different volume fractions of minority phase spheres. Coupled with the movement, thermal and mass transfers during the atomized droplet flight, the numerical model was resolved. The kinetics of metastable liquid-liquid phase transformation in Cu-based immiscible alloys was investigated by numerical simulation. The results indicate that the average size of Fe-rich spheres increases with the increase of Fe concentration. The nucleation event takes place around the peak of matrix liquid supersaturation. With the increase of cooling rate, the nucleation undercooling and the nucleation rate increase, but the average radius of Fe-rich spheres decreases. The formation of Fe-poor layer on the large powder surface is the result of the common actions of the Fe-rich spheres＇ Marangoni migration and repulsive interaction between the solid/liquid interface and Fe-rich spheres.