激光快速熔凝Zn-2%Cu包晶合金的显微组织

MICROSTRUCTURE OF Zn-2%Cu ALLOY UNDER LASER RAPID MELTING-SOLIDIFICATION

利用5 kW连续波CO2激光器对Zn-2％Cu包晶合金进行了表面快速熔凝实验研究,扫描速率从6 mm/s至1207mm/s.随着凝固速率的提高,该合金微观组织形态由低速平界面向层片状组织、浅胞晶直至高速绝对稳定平界面转变.实验结果表明,该合金微观组织演化规律与利用林鑫等的数值模型和Jackson-Hunt的共晶模型相结合所得到的界面响应函数作出的预测结果吻合较好.

Laser surface remelting experiments have been performed on Zn-2%Cu alloy with a 5 kW continous wave CO2 laser. With increasing scanning rate from 6 mm/s to 1207 mm/s, the microstructure transition from light band to lamellar structure, cell, and finally to absolute stability planar, has been clearly observed in the laser molten pool. The experiment results are in good agreement with the prediction of interface response function calculated with Lin's numerical model for cellular/dendritic growth and Jackson-Hunt model for eutectic growth.