In the present study, hot workability of Monel K 500 alloy has been investigated over the temperature range of 850 °C to 1100 °C and strain rate (<InlineEquation ID="IEq1"> <EquationSource Format="TEX">$\dot{\varepsilon }$</EquationSource> <EquationSource Format="MATHML"><math> <mover accent="true"> <mi>ε</mi> <mo>˙</mo> </mover> </math></EquationSource> </InlineEquation>) range of 10−3 to 10 s−1, using isothermal hot compression tests, in a GleebleTM thermomechanical simulator. Dynamic Material Modelling delineated the stable processing domain at T > 1000 °C across all strain rates, exhibiting peak power dissipation efficiency (η) of 49 pct and strain rate sensitivity (m) of 0.3 at 1000 °C/10–3 s−1. EBSD analysis confirmed dynamic recrystallization dominance via characteristic ‘necklace’ microstructures with nucleation at twin boundaries, corroborated by activation energy calculations for DRX onset. Finite element simulations revealed adiabatic heating-induced flow localization and friction-constrained dead zones (<InlineEquation ID="IEq111"> <EquationSource Format="TEX">$\dot{\varepsilon }$</EquationSource> <EquationSource Format="MATHML"><math> <mover accent="true"> <mi>ε</mi> <mo>˙</mo> </mover> </math></EquationSource> </InlineEquation>eff ≈ 0), accounting for center-periphery microstructural gradients. Arrhenius strain-compensated constitutive model σ = f(ε, T, <InlineEquation ID="IEq1110"> <EquationSource Format="TEX">$\dot{\varepsilon }$</EquationSource> <EquationSource Format="MATHML"><math> <mover accent="true"> <mi>ε</mi> <mo>˙</mo> </mover> </math></EquationSource> </InlineEquation>) accurately captured flow stress evolution, incorporating Zener–Hollomon parameter dependence. These coupled thermo-mechanical-microstructural analyses establish T > 1000 °C as the optimal hot working window, providing quantitative formability criteria linking DRX kinetics, stability domains from processing map, and field heterogeneities essential for defect-free Monel K500 manufacturability.

Optimization of Hot Workability and Control of Microstructure in Monel K500: A Study Using Processing Maps, Constitutive Equations and FEM Analysis

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发表日期：

2026年3月30日

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Soumyajyoti Dey,
Ravi Ranjan Kumar,
Varsha Florist,
Debasis Tripathy,
P. Chakravarthy,
S. V. S. Narayana Murty

摘要

In the present study, hot workability of Monel K 500 alloy has been investigated over the temperature range of 850 °C to 1100 °C and strain rate ( $\dot{\varepsilon }$ $\dot{ε}$ ) range of 10⁻³ to 10 s⁻¹, using isothermal hot compression tests, in a Gleeble^TM thermomechanical simulator. Dynamic Material Modelling delineated the stable processing domain at T > 1000 °C across all strain rates, exhibiting peak power dissipation efficiency (η) of 49 pct and strain rate sensitivity (m) of 0.3 at 1000 °C/10^–3 s⁻¹. EBSD analysis confirmed dynamic recrystallization dominance via characteristic ‘necklace’ microstructures with nucleation at twin boundaries, corroborated by activation energy calculations for DRX onset. Finite element simulations revealed adiabatic heating-induced flow localization and friction-constrained dead zones ( $\dot{\varepsilon }$ $\dot{ε}$ _eff ≈ 0), accounting for center-periphery microstructural gradients. Arrhenius strain-compensated constitutive model σ = f(ε, T, $\dot{\varepsilon }$ $\dot{ε}$ ) accurately captured flow stress evolution, incorporating Zener–Hollomon parameter dependence. These coupled thermo-mechanical-microstructural analyses establish T > 1000 °C as the optimal hot working window, providing quantitative formability criteria linking DRX kinetics, stability domains from processing map, and field heterogeneities essential for defect-free Monel K500 manufacturability.