Ni75CrxAl25-x合金原子替代行为的微观相场模拟

Microscopic Phase-Field Simulation for Substitution Behavior of Cr Atom in Ni75CrxAl25-x Alloy

摘要:

利用微观相场动力学模型模拟研究873 K时Ni75CrxAl25-x合金中Cr原子的替代规律。在合金沉淀过程中，Cr原子部分替代Al原子格点形成L12结构的γ′相（Ni3Al1-xCrx）。Cr原子在L12相内的占位几率极限值较小，当Cr含量超过3%时，L12相内Cr原子的浓度接近饱和值。在L12相的有序畴界处，Cr原子完全取代Al原子位置，形成稳定的Ni3Cr相（D022结构）。该合金最终沉淀产物为Ni3Al-Ni3Cr混合相。

Abstract:

The substitution behavior of Cr atom in Ni75CrxAl25-x alloy at 873 K was simulated by a microscopic phase-field model. During the precipitation progress, Cr atoms substitute for the Al sublattices partially to form Ni3Al1-xCrx phases (L12 structure). The limits of occupation probabilities of Cr atoms in L12 phases are lower. Cr atom concentration approaches the saturation value in L12 phases when Cr content exceeds 3%. At the ordering domain interface of L12 phases, Cr atoms substitute for the Al sublattices completely, and the stable D022 phases are formed. The final precipitates are mix phases of Ni3Al-Ni3Cr.