M.P. Miller, J.V. Bernier, J.-S. Park, and S.E. Watts
Sibley School of Mechanical and Aerospace Engineering, Cornell
University, Ithaca NY
A. Kazimirov
Cornell High Energy Synchrotron Source, Cornell University, Ithaca NY
Abstract:
This talk
describes a system for mechanically loading test specimens in situ at the A2
experimental station at the Cornell High Energy Synchrotron Source (CHESS)
for the determination of lattice strains and their evolution in multiphase
alloys via powder diffraction. Relatively thin (0.5mm) Iron/Copper
specimens were axially strained using an electro-mechanical loading frame
beyond the macroscopic yield strength of the material. The loading was
halted at multiple points during the deformation to conduct a diffraction
experiment using a 0.8 x 0.5 mm beam of 50 keV x-rays. Entire Debye rings of
data were collected for multiple {hkl}s in both the copper and iron phases
using a mar345 online image plate scanner. Ideal powder patterns were
superimposed on each image for the purpose of geometric correction. The
chosen reference material was Cerium (IV) oxide powder, which was spread in
a thin layer on the downstream face of the specimen. The CHESS data were
validated using in situ data from neutron diffraction experiments.
Polycrystal plasticity simulation results are also presented for comparison.
New directions for the technique include time resolved experiments subjected
to cyclic loading. Some preliminary results from cyclic tests conducted
during the Spring run cycle are presented.
2008 Run
Nov 19th - Dec 22nd
