Abstract: A molecular orbital approach to materials design has recently made great progress. This approach is based on the electronic structure calculations by the DV-Xα cluster method. In this paper recent progress in this approach is reviewed. In particular, it is stressed that New PHACOMP approach is useful for predicting the formation of topologically close-packed (TCP) phases (e.g., σ phase and μphase ) in nickel based superalloys. Compared to the current PHACOMP, New PHACOMP provides a better tool for designing those alloys which are free from such TCP precipitates at service temperatures. In addition, the d-electrons concept is shown for alloy design and development.

Key words: High temperature materials, Ni based superalloys, Alloy design, Molecular orbital method