Microscale mechanism of material removal process on burr defect formation in grinding superalloy honeycomb composites

Nickel-based superalloy honeycomb composite (NBSHC) is indispensable in the extreme fields such as missile, hypersonic vehicles and aeroengine due to the high temperature resistance and light weight. However, the NBSHC is difficult to be machined, and microscale mechanism of material removal process on burr of NBSHC is not clarified, resulting in burrs that are particularly to be formed during conventional processing and clamping methods. To solve these problems, the NBSHC was ground with ice fixation. The simulation models of grinding depth, speed and cutting angle (process parameters) were established considering the grinding path and ice freezing condition for the first time. Based on the simulations, the microscale material removal and process parameters action mechanisms of NBSHC grinding were comprehensively revealed by coupling stress, plastic strain and temperature fields. To verify the mechanisms and obtain the machined quality of NBSHC, the NBSHC grinding experiments were designed by the novel cutting angle analytical model and ice clamp. The results showed the material removal volume and plastic strain increased with the increment of grinding depth, leading to a subsequent increase in burrs. The increasing volume of material removal per time, decreasing force and fracture strength, and thermal softening effects induced by temperature factors dominated in sequence with the increment of grinding speed, resulting that the burr increased initially, decreased subsequently and ultimately increased as the grinding speed incrementally adjusted. Cutting angle affected burr size by influencing the fracture difficulty of burr and thermal softening effects, and the optimal cutting angle intervals were [0°, 30°] and [150°, 180°].