14th International Conference on Shot Peening

Shot peening and deep cold rolling of a single crystal nickel-based superalloy

I. Bogachev, K.M. Knowles, G. Gibson

University of Cambridge, Department of Materials Science and Metallurgy, 27 Charles Babbage Road,

Cambridge, CB3 0FS, UK – ib358@cam.ac.uk , kmk10@cam.ac.uk

Rolls-Royce plc, PO Box 31, Derby, DE24 8BJ, UK – grant.gibson@rolls-royce.com

Introduction

Jet engine turbine blades are manufactured from nickel-based superalloys because of their excellent high-temperature strength, creep and oxidation resistance. To improve blade fatigue resistance, it is desirable to employ surface hardening techniques such as mechanical shot peening (MSP) and deep cold rolling (DCR). In high stress, high temperature environments, surface hardening is thought to retard fatigue crack growth by inducing a surface cold worked layer of material [1,2]. However, fundamental research must be performed on MSP and DCR-treated single crystal superalloy samples to gain a better understanding of the material response and optimise the procedures.

Objectives

The amount and depth of cold work induced by MSP or DCR in samples of a single crystal nickel superalloy CMSX-4 were studied and compared. The evolution of the material microstructure and cold work following annealing heat treatments at 900 °C and 1100 °C was investigated.