Heat Treatments Effects on Nickel-Based Superalloy Inconel 713C

Breno Boretti Galizoni,Antônio Augusto Couto,Danieli Aparecida Pereira Reis

doi:10.3390/met9010047

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) solid solution treatment (1179 °C/2 h) and (3) stabilization heat treatment (1179 °C/2 h plus 926 °C/16 h). 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. The mechanical resistance in creep increases in Inconel 713C by precipitation hardening phase, with γ’ (Ni3Al) formed during the heat treatments. The characterization techniques used were: chemical analysis, hardness testing, X-ray diffraction, optical microscopy and scanning electron microscopy (SEM), EDS analyzes and thermocalculation. 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, carbides were modified through the heat treatments. (M23C6-type) and boride (M3B2 type) identified with the use of the thermocalculation. The heat treatments increase the relative intensity of niobium in the carbides. The hardness test was not achieved because the material was overaged.

Highlights

The severe crisis that hit the economy and, the aeronautics market in the early 21st century, led aircraft and engine manufacturers to develop more efficient products
The second treatment, stabilization heat treatment, was realized in samples that were already solid solution heat treated and it consists of heating with 10 ◦ C per min rate until 927 ◦ C for 16 h followed by air cooling
The analysis presents the variation of the elements a linealong passing through the fields of the with the dispersed phase chemical along elements a line passing through thematrix fields phase, of the along matrix phase, along with the and the carbide veins

Summary

Introduction

The severe crisis that hit the economy and, the aeronautics market in the early 21st century, led aircraft and engine manufacturers to develop more efficient products. New generations of aircraft had aerodynamically improved wings, increased use of composite materials and new aluminum alloys, as well as new manufacturing processes which contributed to weight reduction [1,2,3]. Aircraft engines provide some of the most demanding applications for structural materials. Moderns turbine engines operate at high temperatures and stresses, and engine components are often subject to damaging corrosion, oxidation, and erosion conditions. These engines convert fuel energy into propulsive thrust. During the past several decades, higher engine performance has been achieved by increasing turbine gas temperature and by increasing the efficiency of each engine stage [2,3]

Objectives

Methods

Conclusion