Abstract
The static and fatigue behaviour of hot rolled Fe-31.5Al-3.5Cr [at.%] with addition of zirconium and carbon was studied at different temperatures. The tensile deformation tests were carried out at temperatures ranging from 20 to 600°C. The fatigue crack growth rate (v-ΔK) curves were measured at 20, 300 and 500°C. The best fatigue crack growth resistance was reached at 300°C, while at 500°C the crack growth rate was the highest and the fatigue life the shortest. The predominant fatigue fracture mechanism is transgranular cleavage. However, a number of other micromorphologic features corresponding to various fracture mechanisms were observed: transgranular quasi-cleavage facets, ductile fatigue striations and brittle striations. When tested at high temperatures, the fracture surface in the zone of static rupture contained signs of plastic deformation, whose amount increased with increasing temperature.

Key words
iron aluminides, fracture micromechanisms, fractography, fatigue crack growth

Full text (578 KB)