Lawrence Livermore National Laboratory

Robert Rudd, Hyunchae Cynn, Jae-Hyun Klepeis, John Pask, Lin Yang

The mechanical properties of metal alloys are of interest for many applications. Remarkable progress has been made over the past few decades in developing a computational approach to calculate mechanical properties including strength from first principles using hierarchical multiscale approaches. At LLNL, this approach has been demonstrated for the pure body-centered cubic (bcc) metal tantalum to be a pathway to creating constitutive models that work even in the extreme conditions of high strain rate and high pressures up to a few megabars. The corresponding framework for bcc alloys has not yet been developed.

This alloy strength project has been undertaken to pioneer the theory and computational framework for a first-principles-based predictive description of impurity and alloying effects on the constitutive behavior of materials under extreme deformation. We are focusing on what aspects of the high Peierls barrier alloy materials can be calculated using ab initio techniques; specifically, quantum mechanical techniques are being used to study three strength-related phenomena: solute mobility, substitutional alloy strengthening, and alloy core-structure modification. In addition to the computational work the project is undertaking further development and application of novel diamond-anvil cell experiments to validate results of the computational models. Both the computational and experimental research will enable new capabilities in alloy strength model development.

Ab initio Density Functional Theory Supercells for gamma surface calculations.

Ab initio Density Functional Theory Supercells for gamma surface calculations of body-centered cubic (bcc) metal alloys.

Selected Publications

  1. "Multiphase Improved Steinberg-Guinan Model for Vanadium," R. E. Rudd and J. E. Klepeis, J. Appl. Phys. 104, 093528 (2008).

Maintained by   Lorin X. Benedict