Microstructure and Deformation of 57Fe17Cr25NiSi Austenitic Super Alloy after Arc Plasma Sintering

Abstract

The microstructure and deformation of 57Fe17Cr25NiSi super alloy are investigated in this study. The super alloy was produced from a mixture of granular ferro-scrap, ferro chrome, ferro silicon and ferro manganese raw materials by the casting method and then sintered using arc plasma for 4 and 8 minutes. The super alloy has been proposed in nuclear as well as fossil power plant facilities, such as vessels and heat exchangers. A combination of microscopy investigations by means of X-ray diffraction and high-resolution powder diffraction, optical microscopy, scanning electron microscopy and transmission electron microscopy techniques was conducted in order to obtain detailed information about the deformation of super alloy steel and its microstructures, especially fine structures. It was found that the austenitic super alloy microstructure is composed of dendrites of g-austenite, which are separated by a eutectic structure of Fe-Cr-C alloy. Arc plasma sintering for 4 to 8 minutes leads to a decrease in the area of the eutectic structure at the inter-dendrites and forms micro straine, from 4.60×10-3 to 5.39-4.06×10-4.

Keywords

• aps, hrpd, sem, tem, x-ray diffraction (xrd)