镍基单晶高温合金表面微阵列孔的制备方法及其实验研究

Preparation Method and Experimental Study of Array Microholes on the Surface of Nickel-Based Single Crystal Superalloy

微小孔结构在航空航天、现代医疗、精密仪器等领域有着广泛的应用,但孔径尺寸微小且加工精度要求高,常规的接触式机械加工方式存在切削力致使孔精度较难控制.而电火花加工非接触和无宏观切削力的特点使其在微小孔加工中具有独特的优势.开展镍基单晶高温合金表面微阵列孔制备的实验研究,首先通过低速走丝电火花线切割方法结合精修工艺实现了边长小于340μm菱形微细阵列电极的高精度制备.采用所制备的微细阵列电极在镍基单晶高温合金表面进行微阵列孔加工,探究微阵列孔尺寸的一致性精度、孔壁的表面质量和电极损耗特点,揭示抬刀速度和抬刀模式对微阵列孔的孔壁粗糙度的影响规律,实现了镍基单晶高温合金表面微阵列孔的高效率高精度制备.

Micro hole structure has a wide range of applications in aerospace,modern medical,precision instruments and other fields,but the aperture size is small and the machining accuracy is high,and the cutting force of conventionally contact machining methods makes the hole accuracy difficult to control.However,the characteristics of non-contact and no macroscopic cutting force of EDM make it have unique advantages in the fabrication of micro holes.The experimental study on the preparation of array micro holes on the surface of nickel-based single crystal superalloy was carried out,firstly,the rhomboid array microelectrode with the average edge of less than 340μm was prepared by low speed wire electrical discharge machining(WEDM-LS) combined with finish trim cut.The forming accuracy,surface morphology and element change of the array microelectrode were further analyzed.The array microelectrode was used to process the array micro holes on the surface of nickel-based single crystal superalloy.The uniformity accuracy of the array micro holes,surface quality of the hole wall and electrode loss characteristic were investigated.The effect of cutter lifting speed and cutter lifting mode on the wall roughness of the array micro holes was revealed,which prepared array micro holes with high efficiency and high precision on nickel-based single crystal superalloy.