Place: TMS Annual Meeting 2011, San Diego, California, USA
Bernhard Seiser, Department of Materials, University of Oxford, Oxford, United Kingdom
David Pettifor, Department of Materials, University of Oxford, Oxford, United Kingdom
The group of topologically close-packed (TCP) phases plays an important role in modern alloys and steels. While their precipitation in single-crystal Ni-based superalloys has a detrimental effect on the mechanical properties, the TCP phases are desirable in precipitation-hardened steels. The formation of the TCP phases is attributed to high local concentrations of refractory elements. We discuss that the trend of the structural stability of TCP phases in refractory elements is captured by a simple tight- binding model. We carried out extensive density-functional theory calculations of the tcp phases A15, C14, C15, C36, mu, sigma, and chi in binary refractory alloys and summarize the influence of band-filling and atomic size on TCP phase stability.