Influence of Lithium on The Structural Stability of Two Austenitic Stainless Steels of The Type 316 and 18 Mn-10 Cr

Abstract

Liquid lithium is considered for tritium breeding and reactor coolant applications in fusion reactors. Many studies have been carried out on the corrosion behaviour of austenitic stainless steels of the type Ni-Cr in that liquid metal environment as these steels, especially 316, are envisaged as structural materials in the blanket of the first generation of reactors. Recently the study was extended to various commercial low Ni, Mn-Cr austenitic steels (1). Samples of these materials were exposed at 873 K to pure Li, in static tests, for times ranging from 500 to 1500 hours. The polished cross-sections were investigated by scanning electron microscopy and X-ray microanalysis. It was observed that for all the steels in contact with pure Li, a corrosion layer depleted in Mn and enriched in Ni is formed. In some of these materials, a grain boundary attack was also evidenced in the unterlying matrix.