First Principles Calculation of Stress Induced Amorphization in Armor Ceramics

Abstract

Recent experimental work within the U.S. Army Research Laboratory has identified the formation of nanoscale-sized intragranular amorphous bands leading to a marked reduction in ballistic performance of boron carbide (B4C). This pressureinduced amorphization has been examined through application of the Born stability criterion that imposes restrictions on the relative magnitudes of the elastic constants of a stable crystal. The analysis has been conducted for B4C as a function of structural polytype using ab initio solid-state density functional methods and the results of the pressure evolution of the B4C elastic constants are reported. It is shown that the C-C-C polytype, a minority phase in the B4C lattice, fails at a pressure of =20 gigapascals less than the other polytypes tested in this survey, indicating that it may serve as one of the initial points of failure upon impact.

Open PDF

Document Details

Document Type
Technical Report
Publication Date
May 01, 2011
Accession Number
ADA542606

Entities

People

  • D. E. Taylor
  • J. W. Mccauley
  • T. W. Wright

Organizations

  • United States Army Research Laboratory

Tags

Communities of Interest

  • Energy and Power Technologies
  • Weapons Technologies

DTIC Thesaurus Topics

  • Armor
  • Boron Carbides
  • Bulk Modulus
  • Carbides
  • Computational Chemistry Methods
  • Density Functional Theory
  • Eigenvalues
  • Elastic Properties
  • Equations
  • First Principles Calculations
  • Materials
  • Mechanical Properties
  • Mechanics
  • Military Research
  • Molecular Dynamics
  • Quantum Mechanics
  • Two Dimensional

Readers

  • Materials Science and Engineering.
  • Quantum Chemistry
  • Systems Analysis and Design