Accession Number : ADA330970

Title :   Nondestructive 3-Dimensional X-ray Diffraction Tomography of Stress/Strain Distribution around Fatigue Cracks in Al-Li 2090.

Descriptive Note : Final rept. 7 Jan 96-30 Sep 97

Corporate Author : GEORGIA INST OF TECH ATLANTA SCHOOL OFMATERIALS ENGINEERING

Personal Author(s) : Stock, Stuart R.

PDF Url : ADA330970

Report Date : 17 OCT 1997

Pagination or Media Count : 27

Abstract : Sychrotron X-ray microbeams were used to characterize the three-dimensional distribution of macrotexture associated with asperity formation during fatigue crack propagation in Al-Li 2090 T8E41. Nondestructive techniques were developed, and beams formed by a 10 micrometers diameter collimator were applied. Focus was on the center portion of 12.5mm thick plates where macrotexture correlates with asperity geometry. A very distinct type of mesotexture was found: multiple adjacent grains have nearly identical orientations and form substantial volumes of near-single-crystal (NSC) material. Transitions between differently oriented NSC volumes or an NSC region and more randomly oriented grains seem to bound asperities.

Descriptors :   *STRESS STRAIN RELATIONS, *CRACK PROPAGATION, MICROSTRUCTURE, NONDESTRUCTIVE TESTING, X RAY DIFFRACTION, FATIGUE(MECHANICS), SYNCHROTRON RADIATION, MICROBEAMS.

Subject Categories : Properties of Metals and Alloys
      Mechanics
      Nuclear Physics & Elementary Particle Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE