Effect of Crystalline Structure on Intergranular Failure During Shock Loading
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The effect of crystalline structure on intergranular failure during shock loading has been examined. A suite of dynamic tensile experiments, using plate-impact testing, were conducted on copper (face-centered cubic) and tantalum (body-centered cubic) specimens with different grain sizes (30–200 μm). These experiments were designed to probe void nucleation, growth, and coalescence processes that for these materials are known to lead to failure. For the grain sizes examined in the study, post-impact metallographic analyses show that in copper specimens, during the early stages of deformation, voids were present primarily at general or low-coincidence, high-angle grain boundaries (GBs), irrespective of grain size. In tantalum, while some voids developed along the GBs, an increasing amount of transgranular damage was observed as the grain size increased. A scenario based on the availability of potential nucleation sites and number of slip systems inherent to each crystalline structure is discussed. The role that this availability plays in either promoting or hindering plastic processes leading to damage nucleation and growth is then examined.
KeywordsTantalum Damage Evolution Misorientation Angle Void Growth Void Nucleation
Los Alamos National Laboratory is operated by LANS, LLC, for the NNSA of the U.S. Department of Energy under contract DE-AC52-06NA25396. Funding was provided by the LDRD-DR Grant 20100026.
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