Mechanical behaviour and temperature measurement during dynamic deformation on split Hopkinson bar of 304L stainless steel and 5754 aluminium alloy

On the Taylor–Quinney coefficient in dynamically phase transforming materials. Application to 304 stainless steel

“…This work considers AISI 304 stainless steel, a reference metastable austenitic stainless steel for studying the SIMT process at high strain rates since it shows a large amount of transformed martensite even under adiabatic conditions (Rodríguez-Martínez et al, 2011). The new model sheds light on previous experimental results reporting unusual ð> 1Þ values for the Taylor-Quinney coefficient (Rittel et al, 2006;Jovic et al, 2006;Rusinek and Klepaczko, 2009), apparently related to an exothermal phase transformation, through a differential treatment of the dissipative terms, namely latent heat and heat due to austenite and martensite plastic deformation. Likewise the model accounts for the strong coupling existing between martensitic transformation, strain, strain rate, stress state and heat release, thus allowing to perform a thorough analysis of their influence in the evolution of the ratio of dissipated to plastic power and work.…”

“…2 shows the dimension of the tensile specimen and some features of the finite element model. The geometry of the compression specimen is taken from Jovic et al (2006). The mesh consists of 5000 four-node axisymmetric bi-linear elements with reduced integration, CAX4R in ABAQUS notation.…”

“…In such cases, the measured temperature rise comprises the effects of exothermal phase transformations during which latent heat is released. When this is the case, a simple ratio of the thermal to mechanical power and work, into which this extraneous heat source is included, may yield effective values of b diff and b int which exceed 1, as reported by Rittel et al (2006) for pure iron, by Rusinek and Klepaczko (2009) for Transformation Induced Plasticity (TRIP) steels or by Jovic et al (2006) for austenitic steels.…”

Dynamic necking in materials with strain induced martensitic transformation

“…l h is the latent heat per unit volume of transformed austenite, therefore the last term in the above equation accounts for the heat released due to the exothermic character of the phase transformation. This has been reported by different authors for dynamically phase transforming materials (Rittel et al, 2006;Jovic et al, 2006;Rusinek and Klepaczko, 2009) and rationalized in Zaera et al (2013). By virtue of its contribution, the heat power may strongly increase upon a certain range of strain, thus enhancing the coupling between temperature and transformation: SIMT contributes to heat through a latent heat term and heat, in turn, hinders SIMT.…”

Inelastic heat fraction evaluation for engineering problems involving dynamic plastic localization phenomena

“…This tendency has been notably observed experimentally by Lerch et al [2003] and Jovic et al [2006] on aluminium alloy and stainless Figure 5. Influence of shear strain rate˙ and initial temperatures T 0 on stress invariant, heating and inelastic heat fraction for the HMSQ-FL-ADD-WYS softening model.…”