Abstract Details
Fast Rate Fracture and Dynamic Yielding of Various Single Crystal Aluminum Specimens
Author: Douglas A. Dalton
Requested Type: Poster Only
Submitted: 2009-04-21 16:46:38
Co-authors: D.L. Worthington, P.A. Sherek, N.A. Pedrazas, H.J. Quevedo, A.C. Bernstein, P. Rambo, J. Schwarz, A. Edens, M. Geissel, I.C. Smith, E.M. Taleff, T. Ditmire
Contact Info:
The University of Texas at Austin
1 University Station, #C1510
Austin, TX 78712
USA
Abstract Text:
Fast-rate fracture experiments of aluminum single crystals were performed at tensile strain rates of ~3x106 s-1 on the Z-Beamlet Laser at Sandia National Laboratories. At strain rates of ~106 s-1 to 107 s-1, maximal fracture stress is limited by imperfections in the material, and the length scales of these imperfections control the fracture type.
Using velocity interferometry, we measured the inherent tensile strength of single crystal specimens. The single crystal materials of interest were high-purity aluminum (Al-HP) and 1100 series aluminum (Al 1100). The single crystal Al-HP exhibited the highest spall strength. In addition to measuring tensile strength, we were able to measure compressive dynamic yield stress. We determined that both the Al-HP and Al 1100 had a low dynamic yield stress.
In addition to the single crystal specimens, we studied an Al+3 wt. % Mg (Al+3Mg) alloy at three different grain sizes (29, 44 and 295 µm). The Al+3Mg specimens possessed smaller spall strengths than the Al-HP and Al 1100, but exhibited no dependence on grain size. The Al+3Mg also had the highest dynamic yield stress of all materials.
Fracture analysis and hydrodynamic simulations will also be presented to put the velocity interferometry results into context with the possible causes of failure. We will discuss the role that flaws at various length scales (i.e grain size, impurity atoms and particles) play in both fast-rate fracture and dynamic yielding.
Comments: