Decrease of Ductility Upon Neutron Irradiation in Iron Alloys and Columbium
SourceThe objective of the study is to analyze the change of the work hardening exponent and the decrease of uniform strain at the load instability point due to neutron irradiation from phenomenological dislocation theory comparing the data of aged specimens. The materials used were columbium, pure iron, iron copper, and iron molybdenum alloys. The work hardening exponent decreases mainly from the reason of the less contribution of dislocation to hardening due to obstacle hardening by irradiation. The decrease of uniform strain comes from two reasons. The one is that the critical dislocation density for uniform strain decreases although dislocation multiplication rate increases with irradiation or aging. The other is due to the decrease of the work hardening exponent which becomes the upper limit of the uniform strain.