Skip to main content

Proceedings of a Workshop on Materials State Awareness (2008) / Chapter Skim
Currently Skimming:

Session II: What Is Materials State Awareness?
Pages 9-18

The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.


From page 9...
... AN INTEGRATED VIEW OF MATERIALS STATE AWARENESS R Bruce Thompson, Iowa State University Materials state awareness seeks to estimate the remaining lifetime of individual systems or structures or components, the heart of condition-based maintenance strategies.
Read the entire page →
From page 10...
... Engel 2 and Brewer 3 further developed the methods to predict elemental crystal structures, terminal solubilities, and the phase fields of intermetallic phases. Brewer drew from concepts of spectroscopy and chemical bonding in introducing the electron promotion energy to establish a hybrid elemental electronic structure.
Read the entire page →
From page 11...
... The effective mass describes the shape of the Fermi energy surface in situations at the Fermi energy level where the band filling is subject to electron-lattice potential interaction. The second derivative factor allows electronic property measurements to be useful, sensitive NDE microstructure and alloy stability assessment tools.
Read the entire page →
From page 12...
... 8 If the lattice experiences compressive or tensile stresses B due to solute additions, residual strains, radiation damage, and so forth, then the electronic overlap of d and f orbitals between lattice atoms will cause both changes in the reciprocal lattice and, thus, the size and shape of the bands. Also, the change in the electronic concentration causes a relocation of the Fermi energy level in the band.
Read the entire page →
From page 13...
... 11 Through the use of spaced, properly calibrated EMATs, the speed of sound can assess the temperature in a material. Balashchenkov and Livanov 12 have correlated the elastic behavior to the electronic structure in an expression that connects the speed of sound to the TEP value when performing nondestructive measurements of impurities in solids, indicating the relationship between various physical property measurements.
Read the entire page →
From page 14...
... The Need for Multiple Measurements The significant difficulty of using a single physical measurement to characterize material microstructure, composition, or other properties is that the measurements are dependent on numerous independent variables. Electronic property measurements are dependent on at least three independent electronic properties.
Read the entire page →
From page 15...
... This region can be represented by various morphologies such as pearlite, Bainite, or as spherical carbides in a ferrite matrix. All three satisfy the same phase rule count of phases, but additional property measurements are needed to distinguish the specific microstructural features.
Read the entire page →
From page 16...
... The fundamental limitations of correlating microstructure and properties to NDE measurements result from both the numerous independent variables that each of these properties has and the number of intrinsic property measurements necessary to characterize the number of phases and the microstructural features. Different electronic, magnetic, and elastic measurement combinations offer complementary insights into materials properties, and practices for their selection need to be developed for the appropriate applications.
Read the entire page →
From page 17...
... While this modeling has yet to be extended fully to evaluate detection methodologies, statistical features, and sensitivity versus probed volume, the results to date represent a firm foundation on which systems for materials state awareness and prognosis can be built. VIRTUAL TESTS: MAKING THE MOST OF EXPERIMENTAL KNOWLEDGE Brian Cox, Teledyne Scientific Taking advantage of major recent advances in computational methods and the conceptual representation of failure mechanisms, the modeling community is building increasingly realistic models of damage evolution in structural composites.
Read the entire page →
From page 18...
... Specific challenges in designing experiments for informing virtual tests and some promising experimental methods are summarized.
Read the entire page →

Key Terms

  • property measurements
  • state awareness
  • fermi energy
  • phase formation
  • sigma phase

  • alloy phase
  • physical property
  • effective mass
  • steel using
  • maraging steel

  • chemical potential
  • virtual test
  • electronic property
  • phase diagram
  • electronic structure

  • electronic properties
  • intrinsic property
  • using magnetic
  • magnetic parameters
  • microstructural changes

  • free electron
  • elastic waves
  • physical measurements
  • energy surface
  • independent variables

  • residual strains
  • brillouin zone
  • crystal structures
  • thermoelectric power
  • phase rule


    • This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
    More information on Chapter Skim is available.