TY - JOUR
T1 - Deformation and fracture in laser-shocked NiAl single crystals and bicrystals
AU - Peralta, Pedro
AU - Swift, D.
AU - Loomis, E.
AU - Lim, C. H.
AU - McClellan, K. J.
N1 - Funding Information:
This research was supported by the LANL under Contract No. LDRD-DR 20020055DR. P. Peralta and E. Loomis are grateful to Dr. T. Groy and the X-ray facility of the Department of Chemistry and Biochemistry, Arizona State University, for access to the Laue back-reflection equipment. The help of D. Byler and R. Dickerson is also appreciated.
PY - 2005/6
Y1 - 2005/6
N2 - Oriented single crystals and a [3 4 55]/[5 7 17] random bicrystal were used to study dynamic behavior in NiAl due to laser-driven shocks at moderate pressures (3 to 20 GPa). Disks 5 mm in diameter and 100- to 400-μm thick were tested at the TRIDENT facility at Los Alamos National Laboratory (LANL). Particle velocities were measured using laser velocimetry, which showed that shock-speed variations with orientation in monocrystals were consistent with anisotropic elasticity predictions, whereas the bicrystal showed spatial and temporal variations in the velocity field due to the grain boundary. The shocks displayed strong elastic precursors at the free surface, which agrees with transmission electron microscopy observations of a low dislocation density in <100> and <111> monocrystals and in the [5 7 17] grain of the bicrystal. The latter developed a damage zone in the [3 4 55] grain, with cracking and slip present close to the boundary. Orientation-imaging microscopy showed that the boundary produced in-plane misorientation gradients in the bicrystal and that all specimens developed through-thickness lattice rotations, which were more pronounced for the <111> and <110> loading axes. High rotations occurred within 20 μ of the shocked surface and decreased toward the bulk, indicating a fast decay of the plastic shock wave, which explains the strong elastic precursors observed.
AB - Oriented single crystals and a [3 4 55]/[5 7 17] random bicrystal were used to study dynamic behavior in NiAl due to laser-driven shocks at moderate pressures (3 to 20 GPa). Disks 5 mm in diameter and 100- to 400-μm thick were tested at the TRIDENT facility at Los Alamos National Laboratory (LANL). Particle velocities were measured using laser velocimetry, which showed that shock-speed variations with orientation in monocrystals were consistent with anisotropic elasticity predictions, whereas the bicrystal showed spatial and temporal variations in the velocity field due to the grain boundary. The shocks displayed strong elastic precursors at the free surface, which agrees with transmission electron microscopy observations of a low dislocation density in <100> and <111> monocrystals and in the [5 7 17] grain of the bicrystal. The latter developed a damage zone in the [3 4 55] grain, with cracking and slip present close to the boundary. Orientation-imaging microscopy showed that the boundary produced in-plane misorientation gradients in the bicrystal and that all specimens developed through-thickness lattice rotations, which were more pronounced for the <111> and <110> loading axes. High rotations occurred within 20 μ of the shocked surface and decreased toward the bulk, indicating a fast decay of the plastic shock wave, which explains the strong elastic precursors observed.
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U2 - 10.1007/s11661-005-0238-5
DO - 10.1007/s11661-005-0238-5
M3 - Article
AN - SCOPUS:21844456517
SN - 1073-5623
VL - 36
SP - 1459
EP - 1469
JO - Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
JF - Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
IS - 6
ER -