LOADING RATE EFFECT OF TIAL-CR ON FRACTURE-BEHAVIOR AT HIGH-TEMPERATURE

A fracture test of TiAl-Cr was carried out at high temperatures and di fferent loading rates. The result shows that the fracture energy decre ases with increasing loading rate even at temperature 1050 degrees C a t which the ductility of TiAl-Cr has been recovered totally. Increasin g temperature makes the transition happen at a relatively high loading rate. Observation of fracture surface shows that the cleavage corresp onds to the lower loading rate, i.e. a higher energy state, while frac ture surface is composed of blocks and lamellar structures when the lo ading is high and fracture energy is low.