Microstructure and solidification behavior of multicomponent CoCrCux, FeMoNi high-entropy alloys
Microstructure and solidification behavior of multicomponent CoCrCux, FeMoNi high-entropy alloys
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多元CoCrCuxFeMoNi高熵合金的显微组织和凝固行为
DOI：
10.1016/j.msea.2015.06.061
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发表时间：
2015-08-26
期刊：
影响因子：
6.4
通讯作者：
Wang, X. J.
中科院分区：
文献类型：
--
作者：
Wu, P. H.;Liu, N.;Wang, X. J.
富（Fe, Co, Ni）枝晶主要在CoCrFeMoNi和CoCrCu0.1FeMoNi合金中形核，随后发生包晶和共晶反应。CoCrCu0.3FeMoNi熔体中富mo初生枝晶与液体发生准包晶反应，并在准包晶结构边缘向共晶耦合生长转变。随后，残液发生共晶反应。当x >= 0.5时，CoCrCuxFeMoNi合金发生液相分离。同时，在富cu区得到了纳米级的析出物。在CoCrCuxFeMoNi高熵合金中发现了FCC和BCC两种晶体结构。令人惊讶的是，当抗压强度达到3012 Mpa时，CoCrCu0.1FeMoNi合金获得了很高的塑性应变（51.6%）。随着Cu含量的增加，原子尺寸差(R)和电负性差(X)减小，价电子浓度（VEC）、混合焓(H)和混合熵(S)增大。因此，通过本文的研究，FCC和BCC结构混合物形成的价电子浓度（VEC）值范围可以扩大到6.87 ~ 835。在CoCrCuxFeMoNi高熵合金中，正的混合焓导致液相分离。(C) 2015 Elsevier B.V.版权所有
(Fe, Co, Ni) rich dendrites nucleate primarily in CoCrFeMoNi and CoCrCu0.1FeMoNi alloys, followed by peritetic and eutectic reactions. The quasi-peritectic reaction occurs between the primary Mo-rich dendrites and liquids in the CoCrCu0.3FeMoNi melts, and transfers to a eutectic coupled-growth at the edge of the quasi-peritectic structure. Subsequently, eutectic reaction happens in the remnant liquids. Liquid-phase separations have occurred in CoCrCuxFeMoNi alloys when x >= 0.5. Meanwhile, some nanoscale precipitates are obtained in the Cu-rich region. Two crystal structures, FCC and BCC, are identified in CoCrCuxFeMoNi high entropy alloys. Amazingly, a pretty high plastic strain (51.6%) is achieved in CoCrCu0.1FeMoNi alloy when the compressive strength reaches to 3012 Mpa. With the increase of Cu content, atomic size difference (Delta R) and electro-negativity difference (Delta X) decrease while valence electron concentration (VEC), mixing enthalpy (Delta H) and mixing entropy (Delta S) increase. Consequently, the valence electron concentration (VEC) values range for the formation of mixture of FCC and BCC structures can be enlarged to 6.87-835 based on the study of this paper. It is the positive enthalpies of mixing that causes the liquid-phase separation in CoCrCuxFeMoNi high entropy alloys. (C) 2015 Elsevier B.V. All rights reserved.