A Dual-Method EES Framework for Temperature-Dependent Elastic Modulus Simulation and Material Selection in Five Metallic Alloys

Abstract

The paper describes a dual-method Engineering Equation Solver (EES) based simulation tool to calculate the temperature-dependent elastic moduli E(T) for five engineering metallic alloy-type materials: Copper C110, Ti-6Al-4V, Inconel 718, Hastelloy C276, and SS 316L from 20 °C to 600 °C. Two complementary computational techniques were developed and validated: Method A is based on using linear interpolation from experimental lookup tables published in the ASM Handbook, MMPDS-14, Haynes International, and MatWeb; Method B implements quadratic polynomial regression E(T)=aT²+bT+c. Cross-validation of the two methods indicated a maximum deviation of 2.70% for all alloys and the entire thermal range, demonstrating good agreement between the two methods and high predictive accuracy of the polynomial equation model. The five alloys tested exhibited a monotonic decrease in elastic modulus with increasing temperature, with the average elastic modulus decreasing 21.3% at 600 °C when compared to the equivalent elastic moduli at ambient temperature. The alloy Inconel 718 exhibited the greatest relative elastic modulus retention, decreasing only 18.59% at 600 °C from ambient. The maximum thermal stress developed in alloy SS316L (1415 MPa at 600 °C) is primarily due to its relatively high coefficient of thermal expansion (16x10⁻⁶/°C). Results of the thermal sensitivity assessment resulted in the identification of two groups of metal alloys: one group having low sensitivity to temperature fluctuations (Cu C110 and Ti-6Al-4V, |dE/dT| < 0.048 GPa/°C) and a second group having high sensitivity to changes in temperature (Inconel 718, Hastelloy C276, and SS 316L, |dE/dT| > 0.057 GPa/°C). The development of an integrated multi-criteria methodology for evaluating metal alloys based on stiffness, retention loss, thermal sensitivity, and thermal stress produced a ranking of Inconel 718 > Hastelloy C276 > Ti-6Al-4V > Cu C110 > SS 316L, which has provided quantitative criteria that will allow for the selection of alloys that can be utilized in thermally demanding structural applications. The establishment of the dual-method EES process has simplified the entire thermal elastic response of each alloy into three scalar coefficients, which allows for the direct analytical incorporation of those three coefficients into finite element analysis equation solvers and digital twin platforms.