Assessment of a European V–4Cr–4Ti alloy – CEA-J57

About 30 kg of 7 mm-thick plates (grade CEA-J57) were fabricated to support development of vanadium alloys for applications as structural components in future fast neutron fission reactors. After a stress relieve annealing at 973 K, the material exhibited elongated grains and large Ti-rich precipitates oriented in the rolling direction. After final heat-treatment of 2 h at 1273 K, the microstructure was fully recrystallised with remaining aligned large precipitates. Charpy V-notch and tensile specimens were machined in various directions of stress-relieved and recrystallised plates. The fracture energy and the lateral expansion were determined between 113 K and 598 K. Stress-relieved specimens clearly highlighted an anisotropic behavior with both ductile and brittle features while the recrystallized specimens are all ductile: a DBTT of 113 K is suggested. The fracture mode and morphology were related to the microstructure and especially to the Ti-rich precipitate distribution. Additionally, tensile tests were performed at room temperature and between 873 K and 1223 K. The results were consistent with previous results: after a plateau around 400 MPa, a significant decrease in tensile strength is observed above 1023 K. The fracture surfaces always exhibited ductile fracture mode. The present work suggests the good quality of this vanadium alloy.