Analysis of Hot Anisotropic Tensile Flow Stress and Strain Hardening Behavior for Inconel 625 Alloy

Abstract

In this study, hot deformation behavior of Inconel 625 alloy has been investigated from room temperature to 700 °C at an interval of 100 °C with slow strain rates (0.0001-0.1 s−1). Flow stress behavior is significantly influenced by temperature and strain rate changes. Dynamics strain aging behavior has been reported from 300 to 700 °C. Various mechanical properties, namely tensile strength, % elongation, strain rate sensitivity and strain hardening capacity (Hc), have been studied over wide range of temperatures and strain rates. Hc values remarkably improved at higher temperatures which indicate an excellent combination of strength and ductility. Additionally, various anisotropic material parameters, namely Lankford coefficient, normal, planer and in-plane anisotropy and anisotropic index, were evaluated. Furthermore, hardening behavior of Inconel 625 alloy has been analyzed by various flow stress equations like Hollomon, Ludwik, Swift and Voce. Two-stage strain hardening behavior has been noticed at all temperatures. Ludwik and Swift equations represent poor prediction capability at lower strain region. Based on statistical parameter comparison, Voce equation prediction capability is found best in agreement with both strain regions. Finally, the fracture morphology of post-tensile specimens has been studied, indicating ductile–brittle fracture with dimples.