Intergranular fracture of fast reactor irradiated stainless steel

Design and Synthesis of Metals (Tungsten) with Structural Hierarchy for Very High Temperatures

The strength of metals is limited by the weakest link in their microstructures. At high temperature, the weakest link is usually a grain boundary. Mobile dislocations represent another type of weak link. The strength-limitation by this two-level hierarchy of crystal defects can be minimized through microstructure design. Although the strengthening mechanisms differ for grain boundaries and dislocations, it is possible to design microstructural architectures that strengthen both. The design must take the stress state into consideration that the component will encounter during its later use. Processing strategies can then be devised for the synthesis of such components. It is imperative to stabilize the designed microstructure at high temperature because this will determine how well and how long the material will be able to perform. Design, synthesis and stabilization are discussed in the present paper. The lamp filament wire technology is the basis for a new method that enables the synthesis and stabilization of artificial microstructures in high-temperature materials.