Tensile properties and fracture toughness of zirconium-8.6 wt. percent aluminum after fast neutron irradiation

The effect of fast neutron irradiation at 600 K on the tensile properties and fracture toughness of the Zr-8.6 wt. percent Al reference material has been studied for fluences up to 2.4 x 1025 n.m-2 (E > 1 MeV). For neutron fluences < 1025 n.m-2, the yield stress at 573 K increases with fluence and the ultimate tensile strength remains unchanged from the unirradiated value. The plastic elongation decreases with increasing fluence. For neutron fluences > 1025 n.m-2, all the Zr-8.6 wt. percent Al specimens exhibited an elastic response with no ductility, i.e., they failed in a brittle manner. Fracture toughness decreases with increasing neutron fluence from a value of 73 MPa.msup(1/2) for the unirradiated material to a low of 0.44 to 7.1 MPa.msup(1/2) for specimens irradiated to a fluence of 2.3 x 1025n.m-2. These changes in tensile properties are explained in terms of irradiation-induced disordering/amorphousness of th Zr3Al intermetallic. (author)