Show simple item record

dc.contributor.authorHe, Baopingen_US
dc.date.accessioned2014-03-14T21:19:14Z
dc.date.available2014-03-14T21:19:14Z
dc.date.issued1992-01-15en_US
dc.identifier.otheretd-09232008-144700en_US
dc.identifier.urihttp://hdl.handle.net/10919/39459
dc.description.abstractDisplacement fields from point-like defects are investigated by x-ray diffraction. The atomic volume changes in the interstitial compounds using crystallographic information has been found to correlate with the size of filled octahedral sites. Systematic correlations enable estimates to be made of the components of the dipole tensor for interstitials in octahedral sites for binary systems containing N, C, and 0 in V, Nb, Ta, Cr, Mo, W, and Fe lattices. X-ray diffraction analysis of the concentration and residual stress gradients in N implanted Mo crystals and Nb films show that the dominant source of internal strain arises from N located in octahedral sites. For Nb implanted at LNT, these distortion centers are aligned equally along three mutually perpendicular directions to maintain cubic symmetry. Large biaxial residual strains are developed after a 5at% implantation of N into Nb and Mo. Radiation damage is present as small vacancy and interstitial loops. A method was developed to obtain the orientation function for samples containing a fiber texture. A slit correction is included and the final results from this simplified approach are compared with the pole figure measured by direct x-scanning. Knowing the orientation function allows one to correct the integrated intensities to that for an ideal powder, thereby allowing thermal and static displacements to be obtained from textured samples. Anisotropic displacements about coherent Be rich GP zones were investigated in a Cull-at%Be alloy. The results indicate that the attenuation factor 2M which determines the relative integrated intensities of Bragg, quasiline, and static diffuse scattering can be expressed in a simplified form. Experimental data of 2M for aged Cu-Be samples show an anisotropy. The anisotropy increases with increasing aging time when the equiaxed-GP zones formed in the early stage collapse into platelike GP zones.en_US
dc.format.mediumBTDen_US
dc.publisherVirginia Techen_US
dc.relation.haspartLD5655.V856_1992.H4.pdfen_US
dc.subjectPoint defectsen_US
dc.subject.lccLD5655.V856 1992.H4en_US
dc.titleX-ray diffraction from point-like imperfectionen_US
dc.typeDissertationen_US
dc.contributor.departmentMaterials Engineering Scienceen_US
dc.description.degreePh. D.en_US
thesis.degree.namePh. D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen_US
thesis.degree.disciplineMaterials Engineering Scienceen_US
dc.contributor.committeechairHouska, Charles R.en_US
dc.contributor.committeememberSmith, Charles W.en_US
dc.contributor.committeememberLytton, Jack L.en_US
dc.contributor.committeememberFarkas, Daniel R.en_US
dc.contributor.committeememberRao, Satish I.en_US
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-09232008-144700/en_US
dc.date.sdate2008-09-23en_US
dc.date.rdate2008-09-23
dc.date.adate2008-09-23en_US


Files in this item

Thumbnail

This item appears in the following Collection(s)

Show simple item record