Laser-Induced Spall of Aluminum and Aluminum Alloys at High Strain Rates

Abstract

Articles you may be interested inHigh repetition rate laser-induced breakdown spectroscopy using acousto-optically gated detection Rev. Sci. Instrum. 85, 073104 (2014) This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Abstract. We conducted laser-induced spall experiments aimed at studying how a material's micro structure affects the tensile fracture characteristics at high strain rates (>10* s''). We used the ZBeamlet Laser at Sandia National Laboratory to drive shocks and to measure the spall strength of aluminum targets with various microstructures. The targets were recrystallized, high-purity aluminum (Al-HP RX), recrystallized aluminum + 3 wt.% magnesium (Al-3Mg RX), and cold-worked aluminum + 3 wt.% magnesium (Al-3Mg CW). The Al-3Mg RX and Al-3Mg CW are used to explore the roles that solid-solution alloying and cold-work strengthening play in the spall process. Using a line-VISAR (Velocity Interferometer System for Any Reflector) and analysis of recovered samples, we were able to measure spall strength and determine failure morphology in these targets. We find that the spall strength is highest for Al-HP RX. Analysis reveals that material grain size plays a vital role in the fracture morphology and spall strength results.

Temperature and high strain rate dependence of tensile deformation behavior in single-crystal iron from dislocation dynamics simulations

“…The dependence of the flow stress with strain rate in many materials shows two clearly differentiated regimes [1,2,3,4,5,6,7,8,9,10], namely a slow increase up to strain rates on the order of 10 7 s −1 followed by a sharp upturn at higher rates. This shift is believed to be related to a transition in the mechanism of dislocation glide, namely from thermally-activated to viscous drag.…”

High performance computing simulations of spall phenomenon in a submicron thick nanocrystalline aluminum

“…A series of plate-impact experiments [7] were conducted with impact velocities in the range of 0.45-2.35 km s −1 on specimens with thickness in the range of 2-3 mm to study the spall strength in the range of 0.8-1.68 GPa for seven microstructural conditions of Al, including three grain sizes of 6061 Al alloy, both ultra-pure and commercially pure 1060 polycrystalline Al, and single crystal Al with two different orientations. Experiments were conducted [8] on specimens of 200 and 500 μm thicknesses at induced maximum strain rates of 10 6 s −1 and the effect of microstructure on the spall strength was discussed for several recrystallized Al HP microstructures generated with different treatments such as grain size reduction, solid-solution alloying, and cold working.…”

“…The increasing influence of strain rate on spall strength was explored in several studies [11][12][13][14]. Experiments [5][6][7][8][9][10][11][12][13][14] were carried out under conditions that generated strain rates in the range of 10 5 -10 7 s −1 . These studies suggested that the strain rates generated during shockwave propagation had a significant effect on the spall strength.…”

Nanovoid nucleation by vacancy aggregation and vacancy-cluster coarsening in high-purity metallic single crystals

“…71 Thus, experiments show that spall failure in polycrystalline materials changes from intergranular and transgranular to purely transgranular as the strain rate increases. 72,74,75 In the limiting case of extremely high strain rates, initial flaws and defects present in the system do not have time to operate and nucleation is believed to occur almost simultaneously throughout the spall plane, the theoretical limit thus being reached. 72 Such limit, known as ultimate spall strength, can be estimated as…”