https://nova.newcastle.edu.au/vital/access/ /manager/Index ${session.getAttribute("locale")} 5 https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:38553 Wed 13 Mar 2024 14:13:38 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:22766 Wed 11 Apr 2018 10:54:34 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:46021 2AlC purity. Aside from a thin oxide layer on the coating surface, a pure Ti₂AlC layer was formed immediately below. In total, the coatings were found to exist as seven microstructurally unique sub-layers due to equilibration of supersaturated phases formed during the laser cladding process. No delamination between any layers was observed. The phase identification and microstructure, as determined using XRD, SEM and EDS, are described in detail. Some unique microstructures were observed, including dendritic Ti₂AlC MAX phase grains produced from a topochemical reaction between TiC_x and Ti_yAl_z regions, and α-Ti supersaturated with up to 33 at.% C. The kinetically trapped phases produced within the coating using this process may offer a strong combination of material properties which could be advantageous for use in extreme environments.]]> Wed 09 Nov 2022 15:31:01 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:19030 3SiC₂ irradiated by 700 keV C ions has been investigated over a range of fluences and sample temperatures. The samples were analysed using a series of experimental techniques, including glancing-incidence X-ray diffraction, Rutherford backscattering spectrometry, Raman spectroscopy and scanning electron microscopy. This material exhibits a high level of tolerance to damage, especially at high temperature. Irradiation at temperatures from room temperature to 270 °C results in decomposition to TiC; however, this is not observed at temperatures above 270 °C. A minimum in the observed damage level is evident for irradiation at a sample temperature of 350 °C. At higher temperatures the damage level increases, and results in material which is made up of damaged Tii₃SiC₂.]]> Sat 24 Mar 2018 08:05:28 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:26983 15 ions cm⁻². The evolution of microstructure and induced defects of the irradiated sample with different doses was surveyed by combining grazing incident X-ray diffraction (GIXRD) using synchrotron radiation and variable energy positron beam analysis (PBA). With increasing irradiation dose, the crystallinity degrades gradually and leads to a combination of damaged Ti₃SiC₂ in combination with the precipitation of a TiCₓ phase. For high dose irradiation, a nano-dispersed TiCₓ phase becomes the dominant component. The PBA measurements indicate the formation of a new large vacancy-type defect that could be a cluster or void. The combination of GIXRD and PBA demonstrates that the damage of the MAX phase is more serious in the first 10 nm surface layer than that in the deeper layers closer to the final resting position of the projectile in the solid. The possible damage mechanisms have been discussed.]]> Sat 24 Mar 2018 07:26:59 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:22092 0.67. It was found that a TiC nanocrystalline phase was formed under the high dose irradiation. However, a complete decomposition by irradiation did not take place even at 10.3 dpa. Post irradiation annealing to temperatures of 500–800 °C results in crystal regrowth of Ti₃SiC₂ and TiC phases.]]> Sat 24 Mar 2018 07:15:15 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:32643 n+1AX_n phase elastic constants as previously predicted by density functional theory calculations is confirmed experimentally for Ti₃AlC₂ to be c₄₄=115.3 ± 30.7 GPa. In contrast, Ti₃SiC₂ is confirmed to be shear stiff with c₄₄=402.7 ± 78.3 GPa supporting results obtained by earlier elastic neutron diffraction experiments.]]> Mon 02 Jul 2018 14:47:12 AEST ]]>