Nickel-rhenium compound sheds light on the potency of rhenium as a strengthener in high-temperature nickel alloys

Article

关键词: SHORT-RANGE ORDER;    RAY-ABSORPTION SPECTROSCOPY;    AUGMENTED-WAVE METHOD;    NI-BASE SUPERALLOYS;    EXTENDED X-RAY;    ATOM-PROBE;    1ST-PRINCIPLES CALCULATIONS;    BRILLOUIN-ZONE;    BINARY-ALLOYS;    ADDITIONS;   

DOI  :  10.1103/PhysRevB.90.094110

来源: SCIE

【 摘 要 】

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 (Ni4Re). 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 Ni4Re 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 approximate to 930 K when considering configurational entropy. The existence of this compound is investigated using extended x-ray absorption fine spectroscopy on a Ni96.62Re3.38 alloy.

【 授权许可】

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