The characterization of creep crack growth rate and its life of TiAl inter-metallic compound with full lamellar microstructure

Abstract TiAl inter-metallic compound is considered to be an effective material for high temperature structural materials. Since, this material is considered to be a creep brittle like material, it is necessary to construct the prediction law for the life of creep crack growth. The introduction of a fatigue pre-crack was found to be difficult due to material structure. Therefore, the validity of using a sharp-notched specimen (machined or EDM) instead of a fatigue pre-cracked specimen to perform creep crack growth rate test (CCGR test) has been proposed. In this paper, creep crack growth tests were conducted for this material using CT specimens with a sharp notch. On the basis of a thermally activated process, CCGR of TiAl inter-metallic compound with full lamellar microstructure was characterized in terms of temperature and stress component and Q ∗ parameter for this material is derived. Furthermore, the algorithm of predicting the life of creep crack growth based on the Q ∗ parameter was derived. This equation was found to well predict the life of creep crack growth.