CA法研究超声频率对激光熔覆凝固组织的影响

Effect of ultrasonic frequency on solidification microstructure in laser cladding using CA method

综合考虑超声的空化作用和声流效应,通过元胞自动机将超声振动作用模型耦合到激光熔覆凝固过程的晶粒形核模型中,研究超声频率对激光熔覆TiC/FeAl凝固组织的影响,并采用直线截点法定量分析凝固组织随超声频率的变化规律,同时采用自行设计的超声振动工作台制备超声辅助激光熔覆TiC/FeAl复合涂层。结果表明:超声的空化作用及声流效应促使激光熔覆TiC/FeAl凝固组织细化,组织及TiC颗粒分布较为均匀;凝固组织随超声频率的增大先细化后粗化,且振动频率为20 k Hz时晶粒细化效果最佳,达到16.7%。模拟计算结果与试验结果一致。

Considering the effect of ultrasonic cavitation and acoustic streaming,the ultrasonic effect model was coupled to the grain nucleation model of laser cladding by cellular automata.The effect of ultrasonic frequency on solidification microstructure in laser cladding TiC/FeAl was investigated,and the rule of microstructure change with ultrasonic frequency was quantitatively analyzed by the method of straight-line node.The TiC/FeAl composite coating was prepared by ultrasonic laser cladding assisted with the self-designed ultrasonic vibration table.The results show that the microstructure in laser cladding TiC/FeAl is refined by the effect of ultrasonic cavitation and acoustic streaming,and the distribution of microstructure and TiC particles is more uniform.The microstructure is refined firstly and then becomes coarse with ultrasonic frequency.The best refinement effect reaches 16.7% when the ultrasonic frequency is 20 k Hz.The simulation results are consistent with experimental results.