Characterization of mechanical properties degradation using small punch testing technique

摘要

A small punch (SP) testing technique developed at Ames Laboratory and its application to mechanical properties degradation evaluation are summarized. It has been clearly demonstrated on ferritic alloys that the SP test is capable of examining the intergranular embrittling potency of segregated P, Sn and Sb causing temper embrittlement, and the effects of neutron irradiation and post-irradiation annealing, giving rise to changes in the hardness and intergranular solute segregation, on the fracture properties in terms of the ductile-brittle transition temperature (DBTT). A linear relationship between the DBTTs obtained by the SP and Charpy V-notched tests has been theoretically and experimentally established. In model Al alloy substrates coated with Ni-P amorphous (10 (mu)m thick) and overlaying ceramics (0-1.0 (mu)m thick), the global and local fracture properties were well characterized by the SP test together with acoustic emission techniques.