| Popis: |
Spray-formed materials are characterized by fine and homogeneous microstructures and typically show much better hot workability than conventional materials. On the other hand, porosity is commonly present in spray-formed materials, and in the worst case cracks and significant segregation may appear. Over the past two decades, a considerable amount of research has been devoted towards characterization of spray-formed materials. A variety of techniques have been used to investigate them with regard to material homogeneity, porosity, grain structure, phases, solid solubility, inclusions and hot workability. For example, segregation has been investigated by means of SOES/GDOES on the macro scale and by means of electron microprobe analysis on the micro scale. Porosity has been measured and studied by means of the Archimedes’ method, optical microscopy and image analysis techniques. Microstructures have been examined and evaluated by means of optical microscopy, XRD, SEM + EDX, etc. Size, shape, and distribution of precipitates/carbides have been quantitatively evaluated by means of image analysis. Deformation behavior of spray-formed materials has been studied by means of compression tests. In addition, soundness has been analyzed by color penetration tests. This chapter will focus on the characterization of spray-formed materials in the last two decades. The most effective and widely used techniques for the material characterization will be described, and the representative results of the investigations will be presented. |
