Gamma double prime precipitation kinetic in Alloy 718
Gamma double prime precipitation kinetic in Alloy 718
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DOI：
10.1016/j.msea.2007.08.046
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发表时间：
2008-06-15
期刊：
影响因子：
6.4
通讯作者：
Heritier, P.
中科院分区：
文献类型：
--
作者：
Devaux, A.;Naze, L.;Heritier, P.
使用 943 至 1003 K 之间的等温和等时时效热处理对合金 718 中的伽马双素 (gamma'') 析出物进行了研究。结果表明，伽马'' 析出物的粗化行为遵循 Lifshitz-Slyozov-Wagner (LSW) 理论的粗化动力学预测。 γ'' 生长的活化能已确定为等于 272 kJ mol(-1)，并且似乎是由基质中钼的体积扩散控制的。通过假设伽马''沉淀物采用使总能量最小化的圆盘形状，伽马''/基质界面的能量Gamma被发现为95+/-17mJ m(-2)。该能量包括根据埃谢尔比包含理论计算的体积变形项和假设为各向同性的表面分量。对该界面能进行了讨论，并与其他高温合金中γ'/基体和γ''/基体界面的能量进行了比较。使用界面能值和γ''沉淀粗化的活化能计算了LSW定律时间依赖性的常数K''，并且发现与我们的实验值非常一致。 (C) 2007 Elsevier B.V. 保留所有权利。
Gamma double prime (gamma ''), precipitation was studied in Alloy 718 using isothermal and isochronal aging heat treatments applied between 943 and 1003 K. It is shown, that the coarsening behavior of gamma '' precipitates follows the coarsening kinetic predictions of the Lifshitz-Slyozov-Wagner (LSW) theory. The activation energy for gamma '' growth has been determined as equal to 272 kJ mol(-1) and seems to be controlled by volume diffusion of mobium in the matrix. The energy of the gamma ''/matrix interface, Gamma, has been found to be 95 +/- 17 mJ m(-2) by assuming that the gamma '' precipitates adopt a disk shape which minimizes the total energy. This energy includes a volume distortion term calculated from the Eshelby inclusion theory and a surface component which is assumed to be isotropic. This interfacial energy is discussed and compared with the energy of gamma'/matrix and gamma ''/matrix interfaces in other superalloys. The constant K '' of the LSW law time dependence has been calculated using the value of interfacial energy and the activation energy of gamma '' precipitates coarsening and is found to be in good agreement with our experimental values. (C) 2007 Elsevier B.V. All rights reserved.