Outstanding Technology Development 2013
Heat-resistant alloys contain a variety of elemental components that are hard to control during the melt-solidification processing stage. As a result, subsequent heat treatment is needed to disperse these elements via diffusion uniformly throughout the ingot. Traditionally, carefully controlled trial and error procedures are used, based on historical best practices. Until recently, this approach was acceptable to produce a "homogenized" ingot or casting. However, as more of these hard to diffuse elements have been incorporated into newer alloy systems, traditional methods of homogenization are no longer appropriate. Unless these elements are uniformly dispersed within the ingot, the microstructure is critically unstable with respect to long-term, high-temperature performance. NETL has developed a computational algorithm using commercially available thermodynamic and kinetic software to design a customized homogenization schedule that delivers a predetermined and desired level of homogenization to an alloy using conventional furnace capabilities.