Performance of grinding nickel-based single crystal superalloy: Effect of crystallographic orientations and cooling-lubrication modes

Abstract

High-strength and high-temperature resistant nickel-based single crystal (SX) superalloys are employed as a key material system for improving aeroengine component performance. Nevertheless, uncertainties associated with crystallographic anisotropy and the effects of different cooling-lubrication modes introduced during grinding nickel-based SX superalloys complicate the assessment of preformation. Therefore, understanding of performance induced by crystallographic anisotropy and cooling-lubrication modes when grinding nickel-based SX superalloys is a crucial for achieving high component quality. This work assessed the wear characteristics of CBN abrasive tools, surface quality and subsurface morphology when grinding nickel-based SX superalloys in different crystallographic orientations and dry, flood and Minimum Quality Lubrication-palm oil (MQL-PO) modes. The yield strength model with orientation dependence for nickel-based SX superalloy was developed to support for further understanding the anisotropy in grinding forces. Results show that the wear level of CBN abrasive tools is independent on crystallographic orientations. CBN abrasive tools applied different cooling-lubrication modes exhibit specific characteristics in grinding process, such as microchip-deposits – dry grinding; wedge-shaped cracks – flood grinding; oil-film with lubricity – MQL-PO. With crystallographic orientations from the 0° to the 45° orientation and the 45° to the 90° orientation, the trend for predicted values by the yield strength model and for experimental tangential forces both present deceased at first and then increased.