Date of Award
Master of Science in Nuclear Engineering
Committee Member 1
Committee Member 2
Nanocrystalline alloys have always fascinated researchers due to their enhanced properties as compared to their bulk counterparts. There has been a rising interest in the nanocrystalline CuTa alloy system due to its high grain stability for temperatures up to 0.7Tm. In the scope of this thesis we studied the microstructure evolution of proton irradiated Cu-10%Ta 700⁰C and we performed TEM in situ mechanical. Microstructure studies showed increase in phase size with increase in dose, defect imaging in Transmission electron microscope (TEM) showed presence of Stacking Fault Tetrahedra (SFT) with an average size of 4 nm and a number density of 1.5×1022 m-3 and Cu grain size was found to be 77 nm ± 14.76 nm, the grain size in the as received sample was reported to be 70 nm signifying no grain growth due to irradiation. TEM in situ mechanical tests were carried out using compression pillars. Yield stress values of as received sample and the proton irradiated sample were in the same range suggesting little to no hardening due to irradiation. This is confirmed by using dispersed barrier hardening model which relates the microstructure of the alloy to its yield stress, the change in yield stress was found to be 8 MPa due to SFT, confirming the results obtained in the TEM in situ mechanical tests. The obstacle spacing in the material due to SFT was found to be 125 nm, considering grain boundaries and precipitates would only further reduce the obstacle spacing making results from nanomechanical tests viable without worrying about size effects.
Patki, Priyam, "Microstructure Evolution and Tem in situ Mechanical Testing of Proton Irradiated Nanocrystalline Copper Tantalum Alloy" (2018). Open Access Theses. 1435.