Abstract
For many decades, it has been known that rhenium imparts a tremendous resistance to creep to the nickel-based high-temperature alloys colloquially known as superalloys. This effect is so pronounced that is has been dubbed “the rhenium effect.” Its origins are ill-understood, even though it is so critical to the performance of these high-temperature alloys. In this paper we show that the currently known phase diagram is inaccurate, and neglects a stoichiometric compound at 20 at.% Re . The presence of this precipitate at low temperatures and the short-range ordering of Re in fcc-Ni observed at higher temperatures have important ramifications for the Ni-based superalloys. The compound is shown to be stable by quantum mechanical high-throughput calculations at 0 K. Monte Carlo simulations show that it is thermally persistent up to K when considering configurational entropy. The existence of this compound is investigated using extended x-ray absorption fine spectroscopy on a alloy.
- Received 29 January 2014
- Revised 22 July 2014
DOI:https://doi.org/10.1103/PhysRevB.90.094110
©2014 American Physical Society