The purpose of this study was to investigate the effect of annealing to the hardness of high Y2O3-oxide dispersion strengthened (ODS) ferritic steels. The samples were prepared by mechanical alloying method followed by Cold Isostatic Pressing (CIP). After compaction process, the samples were sintered at 1100°C for 1 h in a tube furnace. The crystal structure and morphology of samples were analyzed by X-ray Diffraction (XRD) measurement and characterized by using field emission scanning electron microscope (FESEM), respectively. The hardness of samples was measured by using a micro-Vickers hardness tester with a load of 200 gf at annealing temperature of 600°C, 800°C and 1000°C, respectively. The Vickers hardness value (HV0,2) versus annealing temperature graph showed that the hardness of all samples started to decrease at temperature of 600°C due to grain growth. The hardness value of all samples (1Y and 5Y) identified at this annealing temperature is 855 HV0,2 and 808 HV0, 2, respectively.
Among the challenges for superconducting devices to be applied in industry are the need for high transport critical current density (Jr) and sustainability of the device in different environment. For superconducting material to maintain high 4, effective flux pinning centers are needed. The addition of small size MgO particles in bulk Bi2Sr2CaCu2O8 (Bi-2212) superconductor has been proven to enhance the effective flux pinning centers in the superconducting material. Nevertheless, the flux pinning properties of the superconducting materials may change if they are exposed to radioactive environment. Electron irradiation is one of the common techniques that can be used to study the impact of irradiation on superconducting materials. In this work, a small amount of nanosize MgO particles were used as the flux pinning centers for Bi-2212 superconducting material. The Bi-2212/MgO composite was heat treated and followed by partial melting and slow cooling. Some of the samples were subjected to electron irradiation using the facility at the Malaysian Nuclear Agency. Characterizations of non-irradiated and irradiated samples were performed via X-ray Diffraction Patterns (XRD), Scanning Electron Microscopy (SEM) and measurements of J, dependence on temperature in self-field. Higher J, indicates better flux pinning properties in irradiated superconductor composite. This is achieved if defects with larger radius with dimension comparable to the coherence length of the superconducting material were created. On the other hand, decreased in Je indicates ineffective flux pinning and this is attributed to the overlapping of defects that break the superconducting region. Our study showed that electron irradiation deteriorated the flux pinning properties of the Bi-2212/MgO superconductor composite.