Moshokoa Nthabiseng Abigail

PhD candidate at the University of Johannesburg

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Deformation behaviour of metastable binary Ti-Mo alloys

This study aims to activate different combinations of phases and deformations mechanism in the designed binary Ti-Mo alloys using the d-electron methods and Molybdenum equivalence. The four designed binary alloys: (Ti-xMo, x= 10.02, 10.83, 12.89 and 15.05 Wt% Mo) were fabricated using the commercially available arc re-melting furnace. To evaluate the accuracy of the two theoretical predictions, different characterization methods such as the X-ray diffraction (XRD), Optical microscope (OM) and Electron Backscatter Diffraction (EBSD) were used to evaluate the phases and microstructures of the binary alloys. Uniaxial compression tests were performed at room temperature to measure the strength and the Micro-Vickers hardness of the compressed samples were analyzed using the Micro-Vickers Hardness Tester. The X-ray diffractions patterns showed peaks belonging to orthorhombic martensitic (αʺ) and BCC (β) phase, and the EBSD phase maps showed the (omega) ω phase. Three deformation mechanisms were observered from OM and EBSD as: thin parallel plates referred as Stress Induced Martensite (SIM), wide bands (Twining), and wavy thin lines (Dislocation slips). The most dominant deformation mechanisms which was of dislocation slip and twining was found in Ti-15.05 Mo alloy. The highest compressive strength was found in Ti-15.05wt% Mo (1193.09 Mpa) while the Micro-Vickers and the elastic modulus of the decreased with an increase in Mo content. This showed that Ti-15.05Mo have the potential to be used in biomedical application.