Dynamic mechanical behavior of K417G superalloy: development of Johnson-Cook constitutive model and its application in single-grit grinding

Abstract

Precision grinding of K417G superalloy, a key material for hot-end components of aero-engines, is plagued by large grinding forces and excessive heat generation. Clarifying the material removal mechanism is a prerequisite for optimizing the grinding process. Although single-grit grinding is a critical method for revealing this mechanism, it suffers from bottlenecks, such as the difficult acquisition of force or stress fields and poor process visualization. Finite element simulation, an alternative approach, cannot be practically applied because of the lack of dynamic mechanical properties data and a suitable constitutive model for K417G. This study systematically investigates the dynamic mechanical behavior of K417G and develops a Johnson-Cook constitutive model with high fitting accuracy. After embedding this model into single-grit grinding simulations, the study further quantifies the effects of undeformed chip thickness and grinding speed on material removal behavior. The results show that the undeformed chip thickness significantly affects the grinding force, chip morphology, and residual stress. This study not only provides a reliable constitutive basis for the simulation modeling of the precision grinding of K417G but also offers key theoretical support for the accurate optimization of grinding processes for aero-engine hot-end components, which has important engineering application value.