The research is to integrate two novel scientific concepts in the design and fabrication of fire-resistant steels. First, instead of carbon, nanosized coherent copper precipitates will be used for primary strengthening. The low carbon content makes the steel readily weldable without pre- or post-heat treatment. Coherent precipitates tend to coarsen slower with increasing temperature, resulting in less strength degradation at higher temperatures. Second, either Nb or Ti will be used as an alloying element to delay the transition to the high-temperature regime in which rapid grain growth, precipitate coarsening, and dislocation recovery may occur, and to promote secondary strengthening by the formation of metal carbide precipitates. The research provides the intellectual basis for designing stronger fire-resistant steels that meet tougher standards, with results that are readily portable to other high-temperature applications such as boilers, turbines and powertrains for enhanced efficiency. Further, this research addresses nanoscale structure-property relationships in ferrous alloys that are often considered to be mature and old-fashioned, an erroneous impression that permeates throughout the community. Outreach activities conducted by the principal investigators will represent the first step to addressing this fallacy, resulting in students who can think about nanotechnology in broader terms, in industrial scientists and engineers who are better informed about modern advances in metallurgy, and in government agencies willing to take a lead in technology developments. With millions of tons of steels being used in buildings, highways, and bridges every year, many opportunities await the development of inexpensive, easily produced, high-performance steels.
