The morphology and size of Fe ± Co rich particles in Alnico 8 specimens thermomagnetically treated at 800³C for various times have been investigated by means of transmission electron microscope (TEM) observations and small angle X-ray scattering (SAXS). Phases rich in Fe ± Co and Ni ± Al were formed during spinodal decomposition. With longer treatment times, as Fe ± Co rich particles coarsened to a critical size, a ®rst splitting took place. When the resultant small particles originating from the ®rst splitting also coarsened, and they reached critical size, a similar secondary splitting occurred. This is attributable to perfect maintenance of the coherent relationship between the Fe ± Co and Ni ± Al rich phases, as well as the negative interaction energy that arose from the large lattice mis®t. The splitting resulted in a sharp decrease in the mean particle diameter and an increase in the mean aspect ratio of the larger particles studied, which is expected to increase the coercive force of the Alnico 8. In addition, the mean particle length always decreased with increasing treatment time.MST/4522

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The sheet metal of a new Ni-based superalloy has been prepared by Electron Beam Physical Vapor Deposition (EB-PVD) technology. The phases, the microstructures and mechanical properties of this alloy before and after heat treatment have been analyzed by X-ray diffractometer, transmission electron microscope, optical microscope, scanning electrical microscope and tensile equipment. Results showed that the size of γ' particles increases gradually and the morphologies of γ' particles changed from spherical shape into cubical shape when temperature increased from low to high. Compared with as-deposited alloy, mechanical properties of heat-treated alloy were improved obviously. It is feasible that superalloy of better properties can be prepared by EB-PVD technology.