Ph.D. Proposal Presentation by Gregorio R. Murtagian
Thursday, June 20, 2002

(Dr. Steven Danyluk, advisor)

"Plasticity Induced Damage in Reciprocating Grinding of Polycrystalline Gamma Titanium Aluminide"


This work will experimentally and numerically study grinding subsurface plastic deformation and cracking on polycrystalline g-TiAl presenting lamellar structure. Subsurface plastic deformation extent and residual stress distribution will be measured from samples after grinding experiments at different operation conditions. A crystal plasticity numerical model will be implemented for the study of deformation of polycrystalline lamellar g-TiAl under moving concentrated loads. This work will analyze how plastic deformation is affected by the lamellae orientation, plastic deformation transfer between grains, strain localization, and grain/grit size. It will also address the relation of this deformation with the cracking observed experimentally. Low speed single scratch test results can be used to check this numerical model, since thermal effects can be neglected in these experiments, and strain rate is not as high as in actual grinding. This work is expected to contribute to the understanding and quantification of non-reversible transformations in g-TiAl under different grinding conditions.