A path to extreme materials science: Progress, plans, and challenges

Bruce A. Remington, Lawrence Livermore National Laboratory

We all have physical intuition about what material strength means. Try to bend a solid metal sample, and it resists. The stronger the material, the less it deforms, for a given applied shear stress. What about strength at exceedingly high pressures and strain rates? Here, our intuition may falter. At the highest pressures, P > 10 Mbar (1000 GPa), there is no controlled data to guide our thinking and test our constitutive models. Does strength continue to increase with pressure, without bound? Does strength continue to rise monotonically with strain rate? Does failure (strength → 0) still occur above a critical strain, at extreme pressure, compression, and strain rate? In the absence of data, questions and uncertainties greatly outnumber answers. It is our goal and plan to create an experimental platform that can reach P > 10 Mbar in metal samples in the solid state (T << T_melt), and under these conditions, determine the sample pressure, compression, temperature, phase, strain, strain rate, and flow stress (strength). The experimental facilities that we will exploit to achieve these conditions are high energy lasers, such as Omega, Trident, and NIF. I will describe our efforts and plans to achieve this goal, review our progress to date, and summarize the challenges that we face along the way.

The P/T Colloquium is
typically held each
Thursday, 3:45–5:00 PM.
Refreshments are served
at 3:15 PM.