Effect Of Strain Rate And Dislocation Density On The Twinning Behavior In Tantalum

Effect of Strain Rate and Dislocation Density on the Twinning Behavior in Tantalum

The conditions which affect twinning in tantalum have been investigated across a range of strain rates and initial dislocation densities. Tantalum samples were subjected to a range of strain rates, from 10-4/s to 103/s under uniaxial stress conditions, and under laser-induced shock-loading conditions. In this study, twinning was observed at 77K at strain rates from 1/s to 103/s, and during laser-induced shock experiments. The effect of the initial dislocation density, which was imparted by deforming the material to different amounts of pre-strain, was also studied, and it was shown that twinning is suppressed after a given amount of pre-strain, even as the global stress continues to increase. These results indicate that the conditions for twinning cannot be represented solely by a critical global stress value, but are also dependent on the evolution of the dislocation density. Additionally, the analysis shows that if twinning is initiated, the nucleated twins may continue to grow as a function of strain, even as the dislocation density continues to increase.

Processing-Structure-Property Relationships in Metals

In the industrial manufacturing of metals, the achievement of products featuring desired characteristics always requires the control of process parameters in order to obtain a suitable microstructure. The strict relationship among process parameters, microstructure, and mechanical properties is a matter of interest in different areas, such as foundry, plastic forming, sintering, welding, etc., and regards both well-established and innovative processes. Nowadays, circular economy and sustainable technological development are dominant paradigms and impose an optimized use of resources, a lower energetic impact of industrial processes and new tasks for materials and products. In this frame, this Special Issue covers a broad range of research works and contains research and review papers.

High-strain, High-strain-rate Deformation of Tantalum