Master's Examination Committee:

With the rapid development in aviation industry, ourishing research to manu-facture alloys that exhibit long service life and reliable is highly in demand. With the constraint of cost and time, modeling of alloys becomes priority to study the material response in extreme conditions of high stress and temperature, particularly in creep. This thesis will highlight the study of utilization of crystal plasticity-based nite-element method to model creep response for titanium-alloys and nickel-based superalloys. The rst part of the thesis studies Ti-6242 alloy creep response that exhibit more plastic strain in a given favorable microstructure prole despite of low stress applied, compared to harder microstructure prole subjects to higher stress. The simulation result shows this phenomena based on Ti-alloys experiments of vary-ing studied microstructure feature under the same loading. In detail, the thesis dis-cusses heavily on the modication of existing crystal plasticity developed by Ghosh, S. et al that encompasses microstructure parameters, such as; grain or colony size, misorientation, lath- thickness, primary- volume fraction, colony aspect ratio t