(中南大学 粉末冶金国家重点实验室，长沙 410083)
摘 要: 利用激光束扫描金属粉末过程中的球化效应，探索了将异形黄铜粉转化为球形粉末的可行途径，研究了激光功率、扫描速度对粉末颗粒球化过程的影响，并对粉末颗粒的熔化、熔滴铺展和收缩球化过程进行了理论分析。结果表明：粉末的球化、铺展和收缩过程非常短暂，分别在10−5、10−2和10−4 s以内完成，且粒度越细，历时越短。熔滴铺展与收缩的协调是成球的关键，理想的球化效果只有在激光工艺参数、粉末物性和球化环境相互协同的条件下才能实现，对于粒度小于50 μm的异形黄铜粉，在激光功率为500 W、扫描速度为30 mm/s时转化为表面平滑、高球形度的黄铜粉。
关键字: 黄铜粉末；激光；球化效应
（Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China）
Abstract:The irregular particle may melt rapidly and then retract to spherical particle through balling effect by laser beam scanning. The approach of transferring irregular brass powder into spherical powder by laser scanning was explored. The influences of laser power and scanning speed of laser beam and the process of melting, spreading and retracting were analyzed theoretically. The results show that the times of melting, spreading and retracting are very short, which are about 10−5, 10−2 and 10−4 s. And the smaller the particle size is, the quicker the process is. When the laser power was 500 W and scanning speed was 30 mm/s, the spherical brass powder is made from irregular brass powder with diameter of 50 μm. The interval between spreading and retracting is crucial to the balling process, and the ideal balling effect occurs only under the condition of good combination of process parameters, powder feature and environment.
Key words: brass powder; laser; balling effect
