Indentation creep performed on nickel based single crystal superalloys

In order to explore the possibility of determining crystallographic creep exponent using an indentation method, extensive finite element simulations were carried out on differently oriented nickel based single crystal superalloys by incorporating a crystal plasticity theory. The results show that the crystallographic symmetry leads to a certain symmetric distribution pattern of stress, and the crystallographic orientation has a remarkable influence on the indentation depth and its propagation rate. The steady state indentation depth propagation rates under different indentation loads were extracted by an extrapolation approach, and the crystallographic creep stress exponent was then obtained by a linear regression method. The creep stress exponents determined by this approach are independent of crystallographic orientation, which shed some light on the evaluation of creep properties of anisotropic high temperature alloy using the indentation method.