Effect of Temperature and Specimen Thickness on Toughness of Nickel Alloy 22

Abstract

Nickel Alloy 22, UNS N06022, is being evaluated for use as the material of construction in permanent containers for spent nuclear fuel in Yucca Mountain, NV. To meet nuclear design criteria, Charpy impact data were required for the N06022 plate material, but conventional full-size specimens exceed the energy capacity of typical 400 J impact test machines, which results in stopping the pendulum during the test. Half-size specimens break with about 40% of the machine energy capacity, but their use raises questions concerning energy scaling to full size equivalent data. To address this, a range of subsize specimens were tested at room temperature using a standard 400 J impact test machine, and full-size, 3/4-size, and 2/3-size specimens were tested on a high energy capacity, 950J machine. Additional tests were performed at temperatures ranging from -196 to +200°C. Impact energy and lateral expansion measurements for the various test conditions are presented, their implications are examined, and a new model for absorbed energy correlation between subsize specimens and full size conventional Charpy specimens is proposed.