Development and experimental validation of the dynamic constitutive model and equation of state for Mo-10Cu alloy

Abstract

This study systematically investigates the mechanical response characteristics of Mo-10Cu pseudo-alloy under various conditions, including temperatures ranging from 298 K to 550 K, strain rates from 1 × 10⁻² s⁻¹ to 5.2 × 10³ s⁻¹, and dynamic impact loads from 134 m/s to 837 m/s. The investigation is conducted using a combination of multi-method crossover experiment and numerical simulations, with accuracy validated through X-ray testing and static penetration test. Using a universal testing machine, Split-Hopkinson Pressure Bar (SHPB) system, and a light-gas gun, the dynamic constitutive behavior and shock adiabatic curves of the alloy under complex loading conditions are revealed. Experimental results demonstrate that the flow stress evolution of Mo-10Cu alloy exhibits significant strain hardening, and strain-rate strengthening. Based on these observations, a Johnson-Cook (J-C) constitutive model has been developed to describe the material's dynamic behavior. Through free-surface particle velocity measurements, the shock adiabatic relationship was obtained, and a Gruneisen equation of state was established. X-ray experimental results confirm that the Mo-10Cu liner can generate well-formed, cohesive jets. The penetration test results show that the maximum penetration depth can reach 243.10 mm. The maximum error between the numerical simulation and the X-ray test is less than 7.70%, and the error with the penetration test is 4.73%, which confirms the accuracy of the constitutive parameters and the state equation. In conclusion, the proposed J-C model and Gruneisen equation effectively predict the dynamic response and jet formation characteristics of Mo-10Cu alloy under extreme loads. This work provides both theoretical support and experimental data for material design and performance optimization in shaped charge applications.