Heat treatments effects on nickeI-based superalloy Inconel 713C

Abstract

The purpose of this work is to study the effect of heat treatments on the microstructure of the nickel-based superalloy Inconel 713C. Three different conditions were studied and the results compared: (1) as cast; (2) solution treatment (1,179°C/2h) and (3) stabilizing treatment (1,179°C/2h plus 926°C/16h). Inconel 713C is normally used in the as-cast condition, an improvement in the 980°C stress-rupture life is often obtained by a solution heat treatment. However, the material in this condition tested under high stress at 730°C shows a marked decreased in rupture life and ductility [1]. The mechanical resistance in creep increases in Inconel 713C by precipitation hardening phase, such γ’ (Ni3Al) formed during the heat treatments [2]. The characterization techniques used was: chemical analysis, hardness test, X-ray diffraction, optical microscope and scanning electron microscopy (SEM), EDS analyzes and thermocalculation. The heat treatments modified the dendritic structure, reducing the acicularity. The SEM and EDS analysis illustrated the γ, γ’ and carbides. The matrix phase (γ), has in its constitution the precipitation of the γ’ phase, in a cubic form, and in some regions, veins of carbides were modified with the heat treatments.