Influence of notch shape and geometry during creep crack growth testing of TiAl intermetallic compounds

Abstract In order to establish the optimum pre-crack shape and geometry for creep crack growth (CCG) testing of high-temperature brittle materials, several shapes of starter notches were evaluated experimentally on TiAl intermetallic compound. Fatigue pre-cracks are frequently inappropriate in these materials because they tend to promote out-of-plane crack growth in the lamellar structured TiAl materials. Based on the experimental results with several notch shapes and also an analytic assessment of stress distribution around notch-tip, a V-notched specimen is proposed as being optimum for generating creep crack growth data in lamellar structured TiAl. A procedure for machining the notches to minimize its effect on the CCG behavior is also outlined.