On Local Phase Equilibria and the Appearance of Nanoparticles in the Microstructure of Single-Crystal Ni-Base Superalloys

被引：43

作者：

Yardley, Victoria ^{[1
]}

Povstugar, Ivan ^{[2
]}

Choi, Pyuck-Pa ^{[2
,3
]}

Raabe, Dirk ^{[2
]}

Parsa, Alireza B. ^{[1
]}

Kostka, Aleksander ^{[1
]}

Somsen, Christoph ^{[1
]}

Dlouhy, Antonin ^{[4
]}

Neuking, Klaus ^{[1
]}

George, Easo P. ^{[1
]}

Eggeler, Gunther ^{[1
]}

机构：

[1] Ruhr Univ Bochum, Inst Werkstoffe, Univ Str 150, D-44801 Bochum, Germany

[2] Max Planck Inst Eisenforsch GmbH, Max Planck Str 1, D-40237 Dusseldorf, Germany

[3] Korea Adv Inst Sci & Technol, Dept Mat Sci & Engn, 291 Daehak Ro, Daejeon 305338, South Korea

[4] ASCR, Inst Phys Mat, Zizkova 22, Brno 61662, Czech Republic

来源：

ADVANCED ENGINEERING MATERIALS | 2016年 / 18卷 / 09期

关键词：

ATOM-PROBE TOMOGRAPHY; GAMMA/GAMMA'-INTERFACES; CREEP; STRESS; ALLOY;

D O I：

10.1002/adem.201600237

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

High-resolution characterization techniques are combined with thermodynamic calculations (CALPHAD) to rationalize microstructural features of single crystal Ni-base superalloys. Considering the chemical compositions of dendritic and interdendritic regions one can explain differences in gamma-volume fractions. Using thermodynamic calculations one can explain, why gamma-nanoparticles are observed in the central regions of large cuboidal gamma-particles and why tertiary gamma-nanoparticles form in the gamma-channels. The chemical compositions of the v-channels and of the newly formed gamma-particles differ because of the Gibbs-Thomson pressure which acts on the small particles. With increasing size of secondary gamma-particles, their shape changes from spherical to cuboidal. Some general thermodynamic aspects including the temperature dependencies of the Gibbs free energy G, the enthalpy H, and the entropy S and site occupancies in the ordered L1(2) (gamma) phase are considered. The importance of cooling rate after homogenization is discussed.

引用

页码：1556 / 1567

页数：12

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