7. Dynamic Thermal Softening Behavior of Additive Materials for Hybrid Manufacturing

Hybrid manufacturing involves both additive and subtractive (machining) processes to achieve the final product. Substantial differences can exist between the mechanical behavior of additively as-built materials compared to their wrought counterparts. As such, the use of wrought material properties for the simulation and optimization of the machining step in a hybrid manufacturing process may produce inaccurate results. The present work uses the NIST pulse-heated compression Kolsky bar to measure the dynamic behavior of both wrought and additively produced Inconel 625 and 17-4 PH stainless steel over a range of temperatures up to 1000 °C and at strain rates of 3000 s⁻¹. The measurement results are correlated to underlying microstructural differences between additive and wrought materials that arise because of the differences between these material processing routes as described in the literature.