Effects of Peak Pressure, Pulse Duration, and Repeated Loading on the Residual Structure and Properties of Shock Deformed Metals and Alloys

Abstract

The residual microstructures and microstructural histories for Ni, Nig₈₀Cr₂₀ (Chromel A), Inconel 600, type 304 stainless steely and Mo, representing a sampling of fee and bcc metals and alloys (having a range of stacking-fault free energies ranging from roughly 21 to 128 mJ/m² for the fcc materials) are described in detail for a range of peak pressures (8 to 120 GPa) and shook pulse durations (0.5 to 14 μs). Changes in the residual microstructures, which range from stacking faults, twins, and related planar arrays for low stacking-fault free energy fcc materials to dislocation cell structures for high stacking-fault free energy fee materials, are described and quantitatively related to residual mechanical properties (e.g., hardness and yield strength). The production of martensite and the mechanism of α′ - martensite formation are described in relation to shock pulse duration and repeated shock loading. The effect of repeated loading on twin production as well as the effect of shock pulse duration are also described for shock-loaded nickel and type 304 stainless steel. Shock pulse duration seems to have little effect on residual microstructure and hardness above about 1 μs pulse duration. These effects are illustrated in experimental summaries of a large spectrum of shocks-loaded data.