On the stochastic nature of material parameters in advanced aero engine materials.

Abstract

In this work, two materials of TiAl and SiC/SiC CMC were investigated. Through experiments, their stochastic fracture behavior was revealed, which determines the use of these materials for new aero engines or gas turbine applications. The material fracture was studied in two ways - destructive i.e. compact tension test (CTT), three point bending test (3PB)) and nondestructive i.e. computed tomography (CT). We performed total 48 3PB tests for CMC material and 29 3PB tests for TiAl material. As a result, a stochastic fracture model was revealed for both TiAl and SiC/SiC CMC samples with lower and upper bounds. The results obtained by computed tomography revealed the dependence of the type of failure on the porosity of the material and the distribution of pores for the CMC samples. The data obtained as a result of experiments on compact tension test showed the random failure of TiAl samples at the micro level and showed how the crack develops by static loading of the samples.