Tensile deformation and fracture micromorphology of an Fe–28Al–4Cr–0.1Ce alloy

Fracture and mechanical properties of a vacuum cast and hot extruded Fe–28Al–4Cr–0.1Ce (at.%) alloy were studied as a function of temperature and strain rate. The tensile deformation tests were carried out at temperatures ranging from 20 to 700°C, at strain rates of ∼10−4 s−1and ∼10−2 s−1. The effects of strain rate and testing temperature are well recognized in the fractographic features. At room temperature the main fracture mechanism is intergranular decohesion with a certain proportion of transgranular cleavage. With increasing temperature the proportion of transgranular cleavage and ductile dimple fracture gradually increase at the expense of intergranular decohesion. The plastic deformation at each testing temperature is more developed at lower strain rate. The changes in the micromorphology of fracture correlate better with reduction of area than with elongation to fracture. Room temperature ductility of 6.5 and 8.6%, was found for the strain rate of ∼10−4 s−1 and ∼10−2 s−1, respectively.