‘ANSWER’ SHORT COURSE ON: X-RAY LINE PROFILE ANALYSIS FOR THE CHARACTERIZATION OF MICROSTRUCTURE IN CRYSTALLINE MATERIALS
Instructor: Prof. Tamás Ungár Dept. of Materials Physics Eötvös University Budapest H-1518, POB 32 Budapest, Hungary E-mail:
Dates: August 6 - 17, 2007 Place: All events (except the seminar at ORNL) will take place in: Dougherty Engineering Building, Room 517 Dept. of Materials Science & Engineering University of Tennessee Knoxville, TN 37996, USA
Contact: Hahn Choo (
; 865-974-3643) Sponsor: ANSWER (Advanced Neutron Scattering netWork for Education and Research) is an International Materials Institute (IMI) at the University of Tennessee and Oak Ridge National Laboratory supported by the National Science Foundation (NSF) under contract DMR-0231320. For questions regarding the ANSWER program, contact one of the PIs: P. K. Liaw (
), H. Choo (
), C. R. Hubbard (
), or Xun-Li Wang (
). Lectures: From Monday, Aug. 6 through Thursday, Aug. 9.
Each lecture is about 75 to 90 minutes long. Throughout the week, local students and research staff will interact with Prof. Ungar to identify research topics for collaboration.
Lecture #1: Monday, August 6, 2:00PM Fundamentals of diffraction on defect crystals on the basis of the kinematical scattering theory Lecture #2: Tuesday, August 7, 10:00AM Long-range internal stresses in materials with heterogeneous dislocation structures; characteristically asymmetric line profiles as a direct evidence for the composite model of plastic deformation Lecture #3: Tuesday, August 7, 2:00PM Long-range internal stresses and small misfits in γ/γ' Ni-base superalloys Lecture #4: Wednesday, August 8, 10:00AM Strain anisotropy, and the dislocation model for strain anisotropy Lecture #5: Wednesday, August 8, 2:00PM The evaluation and use of dislocation contrast factors in the evaluation of microstrain and slip activity Lecture #6: Thursday, August 9, 10:00AM Planer defects in fcc cubic and hexagonal materials Lecture #7: Thursday, August 9, 2:00PM The use of whole profile methods, especially the MWP, CMWP and eCMWP softwares
Practical Sessions: Friday, August 10, 10:00AM ~ Hands-on practical sessions and research interactions until Friday, Aug. 17 Special Seminar Tuesday, August 14 Visit to Oak Ridge National Lab
SEMINAR Tuesday, August 14, 2007 10:00 AM Room 240, Bldg. 4515 (HTML), ORNL Microstructure obtained by X-ray line profile analysis using defect-related profile functions Prof. Tamás Ungár Department of Materials Physics Eötvös University Budapest, Hungary
Abstract The three major types of lattice defects are (i) microstrains, (ii) grain or subgrain boundaries and (iii) planar defects, especially stacking faults and twin boundaries. They are separated from each other in a diffraction pattern on the basis of the different hkl dependences of broadening, asymmetries and/or shifts. It will be shown that physically well established, theoretical profile functions can be attributed to each of the three fundamental defect types. The defect-related profile functions are uniform throughout the entire diffraction pattern. Strain or size anisotropy is accounted for by appropriate hkl scaling of the breadths of the corresponding profile functions. In the case of planar defects, besides the breadths also the positions have to be scaled. The adequately hkl scaled, defect-related profile functions enable to fit a vide range of diffraction patterns. Host: Hahn Choo (
) & Cam Hubbard (
)
