Study on chip formation in grinding nickel-based single-crystal superalloy DD5

According to the significant anisotropy of nickel-based single-crystal superalloy, a three-dimensional single abrasive grinding model based on the Hill model was developed. In this work, the change in the actual grinding thickness (a_g) of the abrasive is taken into account in establishing the model. In addition, a combination of theoretical research and experimental research is used. The surface morphology and chip morphology of DD5 were first studied. Then, the evolution of chip morphology and the change in grinding force were investigated. Finally, the influence of grinding speed (v_s) on chip morphology and chip segmentation frequency (f_c) was studied. The research shows that serrated chips can easily occur when machining DD5 within the range of grinding parameters. The grinding force increased steadily and was accompanied by inevitable periodic fluctuations corresponding to serrated chips. As the grinding speed increased, the abrasive could enter the cutting stage more quickly, and its critical chip thickness (a_cr) eventually decreased from 0.225 μm to 0.158 μm. The percentage of the cutting phase increased from 85% to 89.5%. However, the critical scratch thickness was not significantly influenced by the change in grinding speed. The grinding speed and thickness substantially influence the morphology and segmentation frequency of DD5 chips. Specifically, as the grinding speed continues to increase, the DD5 chip morphology changes from a densely stacked unit nodal shape with serrated subsections to a continuous type of serrated shape and finally develops into a strip-shaped chip. At different grinding speeds, the chip segmentation frequency of DD5 decreases with increasing grinding depth.