Prediction method of radial heat affected zone width in nanosecond pulsed laser ablation of TC4

Abstract

Nanosecond pulsed laser ablation (NPLA) is widely used in micromachining. However, during the machining process, the radial heat-affected zone (RHAZ) will deteriorate the machining quality and accuracy of the microgroove, which is the basic unit of the ridge surface used to reduce frictional resistance in spacecraft walls. Its effective prediction is crucial for the processing precision control of microgrooves to ensure the drag reduction performance of the ridge surface. For this reason, this paper proposes an effective method to predict the RHAZ width. TC4, commonly used in aerospace, is the target material in this work. By comprehensively considering the thermal accumulation effect of laser pulses and the superimposability of the temperature field, and based on the point heat source method, a dynamic temperature distribution model in NPLA is established. Then, the RHAZ width is initially predicted by combining the graphical method and the RHAZ definition. Finally, to improve the prediction accuracy of the RHAZ width. A correction factor is obtained by the NPLA of microgrooves on TC4. The relative error between the predicted RHAZ width and observed values is less than 7% after introducing the correction factor, which verifies the reliability and validity of the proposed prediction method for the RHAZ width. Furthermore, the RHAZ width in NPLA of TC4 is on the order of hundreds of microns, which should be considered to ensure its processing quality when the ridge surface is designed on TC4. The research method in this paper will guide the design of high-density functional patterns and their high-precision preparation and has significant engineering practical value.