Accession Number : AD0739674

Title :   Thermal Activation Strain Rate Analysis (TASRA) for Polycrystalline Metals.

Descriptive Note : Technical rept.,

Corporate Author : MARYLAND UNIV COLLEGE PARK ENGINEERING MATERIALS GROUP

Personal Author(s) : Armstrong,Ronald W.

Report Date : MAR 1972

Pagination or Media Count : 29

Abstract : The thermal activation strain rate analysis, in the formalism of Seeger, is connected with the Hall-Petch stress-grain size analysis for polycrystals to describe the plastic strength of single crystals and polycrystals at various temperatures and strain rates and for various microstructures. Particular attention is given to the Hall-Petch stress concentration factor, and to the constitutive relation predicting that the logarithm of the Hall-Petch 'friction' stress, is linear with temperature. These considerations bear on the purpose of this research contract because the Hall-Petch parameters play a key role in predicting the ductile-brittle transition behavior of certain body-centred cubic and hexagonal close-packed metals. (Author)

Descriptors :   (*DEFORMATION, CRYSTALS), (*CRYSTALS, THERMAL STRESSES), (*METALS, STRAIN(MECHANICS)), CREEP, DISLOCATIONS, TEMPERATURE, GRAIN SIZE, COPPER, IRON, MAGNESIUM, NIOBIUM, MOLYBDENUM

Subject Categories : Metallurgy and Metallography
      Crystallography
      Solid State Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE