Determination of the High Strain Rate Behaviour of a CuCrZr Alloy Using an Electromagnetic Forming Bench Test

Abstract

A novel electromagnetic forming (EMF) bench test has been developed to characterize the dynamic behaviour of metallic materials. This paper presents the specific case of a CuCrZr wrought alloy, detailing both the experimental approach and the inverse numerical methodology. The primary advantage of the proposed method lies in its ability to calibrate a dynamic material model, which is particularly relevant for forming applications involving thin specimens, with thicknesses as low as 0.6 mm. The well-known Johnson-Cook model is used without consideration of the thermal softening term. The calibration is validated within the strain rate range of [1-4000]s-1 . It is indeed shown that this method generates a broad variation of strain rates during the 300 µs test duration. The benefits from using a strain rate sensitive law as opposed to a quasi-static one are also demonstrated. Analysis of plastic strains and peak stresses further indicates that the EMF test is particularly well-suited for ductile materials, whereas brittle materials may fracture prematurely or fail to deform sufficiently. Limitations regarding the non-uniqueness of the calibrated model and the incorporation of thermal effects are briefly discussed.