skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Plasticity Effects in Dynamically Loaded Nickel Aluminide Bicrystals

Abstract

Elastic and plastic anisotropy are believed to play large roles in the dynamic deformation of many materials at the grain-level. More importantly to polycrystalline materials is how velocity and stress perturbations are transmitted across interfaces in anisotropic materials. Very little work has been done in this area even though it is important for understanding shock/grain boundary interactions. Therefore, experiments have been performed using nanosecond laser shocks of grown Nickel Aluminide bicrystals at tens of GPa. Velocity histories were measured along a line on the back (free) surface of the bicrystals and used to characterize the material behavior. Unstable plastic flow in <100> grains was seen to occur when loaded above 700 m/s free surface velocity. Flow stresses in <111> and <100> grains were measured to be 2.9 and 3.3 GPa, respectively. Calculations were performed based on anisotropic elasticity and dislocation motion on primary slip systems to measure plastic flow properties where plastic strain-rates on the order of 10{sup 6} s{sup -1} were calculated using the experimental velocity histories. Definitive evidence of plastic wave scattering at the grain boundary was not observed experimentally; however, behavior across the grain boundary has been measured. The observations show that a smooth transition occurs betweenmore » the elastic precursors in both grains as well as the plastic waves (when plastic flow is evident). An anisotropic elastic-plastic wave scattering model has been developed to explain the mechanisms affecting shock/grain boundary interactions.« less

Authors:
; ; ; ;
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
946250
Report Number(s):
LLNL-JRNL-409228
Journal ID: ISSN 1359-6454; ACMAFD; TRN: US200903%%344
DOE Contract Number:  
W-7405-ENG-48
Resource Type:
Journal Article
Journal Name:
Acta Materialia
Additional Journal Information:
Journal Volume: 56; Journal Issue: 14; Journal ID: ISSN 1359-6454
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ANISOTROPY; BICRYSTALS; DEFORMATION; DISLOCATIONS; ELASTICITY; LASERS; NICKEL; PLASTICITY; PLASTICS; SCATTERING; SLIP; STRESSES; VELOCITY

Citation Formats

Loomis, E, Swift, D, McNaney, J, Lorenzana, H, and Peralta, P. Plasticity Effects in Dynamically Loaded Nickel Aluminide Bicrystals. United States: N. p., 2008. Web. doi:10.1016/j.actamat.2008.03.042.
Loomis, E, Swift, D, McNaney, J, Lorenzana, H, & Peralta, P. Plasticity Effects in Dynamically Loaded Nickel Aluminide Bicrystals. United States. https://doi.org/10.1016/j.actamat.2008.03.042
Loomis, E, Swift, D, McNaney, J, Lorenzana, H, and Peralta, P. Tue . "Plasticity Effects in Dynamically Loaded Nickel Aluminide Bicrystals". United States. https://doi.org/10.1016/j.actamat.2008.03.042. https://www.osti.gov/servlets/purl/946250.
@article{osti_946250,
title = {Plasticity Effects in Dynamically Loaded Nickel Aluminide Bicrystals},
author = {Loomis, E and Swift, D and McNaney, J and Lorenzana, H and Peralta, P},
abstractNote = {Elastic and plastic anisotropy are believed to play large roles in the dynamic deformation of many materials at the grain-level. More importantly to polycrystalline materials is how velocity and stress perturbations are transmitted across interfaces in anisotropic materials. Very little work has been done in this area even though it is important for understanding shock/grain boundary interactions. Therefore, experiments have been performed using nanosecond laser shocks of grown Nickel Aluminide bicrystals at tens of GPa. Velocity histories were measured along a line on the back (free) surface of the bicrystals and used to characterize the material behavior. Unstable plastic flow in <100> grains was seen to occur when loaded above 700 m/s free surface velocity. Flow stresses in <111> and <100> grains were measured to be 2.9 and 3.3 GPa, respectively. Calculations were performed based on anisotropic elasticity and dislocation motion on primary slip systems to measure plastic flow properties where plastic strain-rates on the order of 10{sup 6} s{sup -1} were calculated using the experimental velocity histories. Definitive evidence of plastic wave scattering at the grain boundary was not observed experimentally; however, behavior across the grain boundary has been measured. The observations show that a smooth transition occurs between the elastic precursors in both grains as well as the plastic waves (when plastic flow is evident). An anisotropic elastic-plastic wave scattering model has been developed to explain the mechanisms affecting shock/grain boundary interactions.},
doi = {10.1016/j.actamat.2008.03.042},
url = {https://www.osti.gov/biblio/946250}, journal = {Acta Materialia},
issn = {1359-6454},
number = 14,
volume = 56,
place = {United States},
year = {2008},
month = {12}
}