Influence of pulse duration and frequency of laser surface texturing on the surface roughness and microstructure of CoCr28Mo alloy for biomedical applications

Abstract

This study presents the effects of pulse duration and frequency in laser surface texturing on the surface roughness and microstructure of CoCr28Mo alloy for biomedical applications. Texturing of the alloy surface was performed using 20 W fiber laser marking equipment. The pulse duration ranged from 50 to 300 ns and the frequency from 100 to 200 kHz. Higher frequencies generally correlated with reduced surface roughness, whereas pulse duration exhibited fluctuation. Statistical analyses confirmed the significance of both parameters and their interaction in affecting the surface roughness of the alloy. Optimal conditions with a pulse duration of 200–300 ns and a frequency of 200 kHz suggest potential for achieving a surface roughness less than 2 µm. The lowest surface roughness value of 0.81 ± 0.04 µm was achieved at a frequency of 200 kHz and a pulse duration of 300 ns. After removing the metal from the surface using this frequency and pulse duration during laser texturing, metal residues accumulated on the textured surface in spherical and layered forms, significantly affecting the surface roughness. This study emphasizes the complex relationship between laser surface-texturing processing parameters and surface properties, providing a promising approach for achieving the highly desirable surface roughness for biomedical applications.