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Los Alamos National Laboratory. LA-UR-98-1794. Form No. 836 R5 ST 2629 10/91. 8P.
When treated with intense pulsed ion beams (IPIB), many materials exhibit increased wear resistance, fatigue life, and hardness. However, this treatment often results in cratering and roughening of the surface. In this work, high purity single crystal and polycrystalline copper samples were irradiated with pulses from an IPIB to determine whether this cratering is due to (1) bulk alloy content, (2) impact of anode debris, or (3) grain structure. Samples were treated with 1, 2, 5, and 10 shots at an average energy fluence per shot of 2 J/cm2 and 5 J/cm2 . Shots were about 400 ns in duration and consisted of a mixture of carbon, hydrogen, and oxygen ions at 300 keV. It was found that the single crystal copper cratered far less than the polycrystalline copper at the lower energy fluence. At the higher energy fluence, cratering was replaced by other forms of surface damage, and the single crystal copper sustained less damage at all but the largest number of shots. Molten debris from the Lucite anode (the ion source) was removed and redeposited on the samples with each shot. From this, we conclude that neither bulk alloy content nor anode debris impact cause cratering. Grain structure affects cratering, although the mechanism for this is not determined in this study.
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LA-UR-98-1794 Title: Author(s): Cratering Behavior in Single- and Poly-Crystalline Copper Irradiated by an Intense Pulsed Ion Beam B. P. Wood 1 A. J. Perry 2 L. J. Bitteker 1 W. J. Waganaar1 1 Plasma Physics Group, MS-E526, Los Alamos National Laboratory, Los Alamos, NM 87545 2 A.I.M.S. Marketing, 10921 Corte Calandria, San Diego, CA 92127 Submitted to: http://lib-www.lanl.gov/la-pubs/00412785.pdf Los Alamos National Laboratory, an affirmative action/equal opportunity employer, is operated by the University of California for the U.S. Department of Energy under contract W-7405-ENG-36. By acceptance of this article, the publisher recognizes that the U.S. Government retains a nonexclusive, royalty-free license to publish or reproduce the published form of this contribution, or to allow others to do so, for U.S. Government purposes. The Los Alamos National Laboratory requests that the publisher identify this article as work performed under the auspices of the U.S. Department of Energy. Los Alamos National Laboratory strongly supports academic freedom and a researcher’s right to publish; therefore, the Laboratory as an institution does not endorse the viewpoint of a publication or guarantee its technical correctness. Form No. 836 R5 ST 2629 10/91 Cratering Behavior in Single- and Poly-Crystalline Copper Irradiated by an Intense Pulsed Ion Beam B. P. Wood1, A. J. Perry2, L. J. Bitteker1, W. J. Waganaar1 1 Plasma Physics Group, MS-E526, Los Alamos National Laboratory, Los Alamos, NM 87545 2 A.I.M.S. Marketing, 10921 Corte Calandria, San Diego, CA 92127 Abstract When treated with intense pulsed ion beams (IPIB), many materials exhibit increased wear resistance, fatigue life, and hardness. However, this treatment often results in cratering and roughening of the surface. In this work, high purity single crystal and polycrystalline copper samples were irradiated with pulses from an IPIB to determine whether this cratering is due to (1) bulk alloy content, (2) impact of anode debris, or (3) grain structure. Samples were treated with 1, 2, 5, and 10 shots at an average energy fluence per shot of 2 J/cm2 and 5 J/cm2. Shots were about 400 ns in duration and consisted of a mixture of carbon, hydrogen, and oxygen ions at 300 keV. It was found that the single crystal copper cratered far less than the polycrystalline copper at the lower energy fluence. At