Computational design of recovery experiments for ductile metals

Abstract

Previous work on the shock loading of metals, has shown that one-dimensional strain histories may be only be approximated in a loaded sample if it is to be recovered at late times to examine microstructure. This proceeds through the use of a system of partial momentum traps and soft, shock-recovery techniques. However, limitations in the degree of uniaxial loading, and on the trapping of tensile pulses, have led to redesign of the target. In the current paper the technique is first assessed, and then modifications are explored to further refine it. Additionally it is illustrated how it may be applied to successfully recover targets of lower innate fracture toughness than has been previously documented. In the first part of the paper, the authors review work undergone to shock recover metals, and highlight associated constraints. In the latter part of the paper, a series of hydrocode simulations is presented to illustrate the design of an improved shock recovery technique that has now been adopted.

The study of high-speed surface dynamics using a pulsed proton beam

“…The final geometries are similar to the design seen in Fig. 1, which incorporates momentum trapping concepts (see [12]). Figure 2 shows one late time ×3 magnified image from two of three Fig.…”

Contrasting the effects of cold rolling on the shock response of typical face centred cubic and body centred cubic metals

“…The mechanical response to shock loading was monitored using laterally mounted stress gauges [10] 2 mm from the impact face, and in the case of tantalum, Hetrodyne velocimetry (Het-V; PDV) [11] was used to measure the motion of the free surface. The microstructural response was determined using the techniques of Gray and his colleagues [12,13], and examined using a variety of microstructural techniques (TEM etc).…”

Modifications of the Response of Materials to Shock Loading by Age Hardening

“…However, there still remains the 96 -(a) particle velocity calculated using impedance matching methods, using the published data of Marsh. [40] question as to why the age-induced increases in strength observed at quasi-static strain rates are not observed (at least to the same extent) during shock loading. Again, it is believed that the answer can be found in the recovered microstructures.…”

“…The methodology employed here uses multiple rings of material around the specimen section to trap these lateral releases from entering the specimens, based on the methods developed by Gray and colleagues. [38][39][40] All recovery experiments were performed on aluminum 6061, in both the T0 and T6 conditions. To conserve material, the lateral momentum rings were made from 6082-T6, which is a near identical impedance match to 6061.…”