Investigation of the susceptibility of EUROFER97 in lead–lithium to liquid metal embrittlement (LME)

Abstract

Liquid metal embrittlement (LME) is defined as the brittle fracture (loss of ductility) of usually ductile materials in the presence of a liquid metal. The sensitivity to LME is likely to increase with irradiation hardening as localised stresses can promote the aggressive action of a liquid metal. To investigate the mechanical response of irradiated materials in contact with a liquid metal, an instrumented hot cell has been developed. The testing machine installed inside allows mechanical testing of active materials in liquid lead lithium under well controlled chemistry conditions. Typical mechanical tests that can be carried out are slow strain rate tests (SSRT), constant load and rising load tests at temperatures from 150 °C to 500 °C. In this paper the first results of the SSRT tests with EUROFER97 in argon and lead–lithium at different temperatures with different strain rates will be presented. The SSRT test method has been chosen due to the accelerated nature of the test, i.e., during straining the oxide layer will be ruptured and wetting of the sample surface by the lead–lithium melt is promoted. The results collected up till now showed no sign of LME. Tests with longer pre-exposure times and tests with irradiated samples will be carried out in the next phase. A longer pre-exposure time can enhance wetting and so the susceptibility to LME. An increase of the yield stress due to irradiation can also enhance the susceptibility to LME.