Microstructural study of a nitrogen implanted iron-chromium alloy

The microstructure and phase composition of superficial layers of a nitrogen implanted iron-chromium alloy are investigated by transmission electron microscopy. The observations show some structural transformation of the bcc matrix, the formation of numerous finely dispersed precipitates (nitrides, carbonitrides whose diameter is about 5 nm) and the appearance of a very damaged superficial layer. These changes are considered versus implantation fluence (from 1016 up to 6 x 1017 ions cm-2). The importance of the presence of chromium in the alloy and of the implantation parameters (temperature, quality of vacuum) is discussed. (author)