Study of Mechanical Properties and Microstructural Analysis for Inconel Alloy sheet at Elevated Temperature

Abstract

A reliable and accurate prediction of material properties and flow behavior of metals considering the coupled effects of strain, strain rate and temperature is a crucial parameter for optimizing the workability. In this study, hot uniaxial tensile tests have been performed on Inconel 718 alloy from Room Temperature (RT) to 600°C at an interval of 200°C and strain rates from 0.1 s-1 to 0.0001 s-1. Generally, the anisotropy of rolled sheet influences the material properties, material properties have been determined with respect to rolling direction (RD), Normal direction (ND) and transverse direction (TD). The various material properties such as yield stress (σy), ultimate tensile strength (σu), total elongation and strain hardening exponent (n) have been evaluated over the range of temperatures and strain rates. Considerable variation in the material properties have been noticed with respect to temperature than strain rate. Furthermore, microstructure analysis has been carried out using optical microscopy and Scanning Electron Microscope (SEM). SEM micrographs with EDS analysis of fracture specimens revealed carbides with the non-homogeneous distribution of large number of δ precipitates. SEM study confirms dimples and shear band which indicate predominantly ductile fracture in all the cases