Phase equilibria and microstructure on γ′ phase in Co-Ni-Al-W system
Phase equilibria and microstructure on γ′ phase in Co-Ni-Al-W system
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DOI：
10.2320/matertrans.mer2008073
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发表时间：
2008-06-01
影响因子：
1.2
通讯作者：
Ishida, Kiyohito
中科院分区：
文献类型：
--
作者：
Shinagawa, Kazuya;Omori, Toshihiro;Ishida, Kiyohito
用电子探针（EPMA）和X射线衍射仪（XRD）测定了Co-（10-70）Ni-Al-W体系在900 ℃时γ相和γ '相的相平衡。结果表明，在Co-Ni-Al-W体系中，γ '相从Co侧向Ni侧连续存在，且随Ni含量的增加，γ'相向低W区扩展。随着Ni含量的增加，Al在γ '相中的分配量增加，而W则由γ'相转变为γ相。差示扫描量热法（DSC）的测量也表明，γ '固溶线温度增加与Ni含量，而固相线温度几乎不受这样的内容。随着Ni含量的增加，γ相和γ '相的晶格常数和失配度减小，γ'相由立方相变为球形。
Phase equilibria between the gamma and gamma' phases at 900 degrees C in the Co-(10-70)Ni-Al-W system were determined by electron probe microanalysis (EPMA) and X-ray diffractometry (XRD). It was found that the gamma' phase with L1(2) structure continuously exists from the Co side to the Ni side in Co-Ni-Al-W system and that it widens to the low W region with increasing Ni content. The partition of Al into the gamma' phase increased with Ni content, while the W changed from a gamma' former to a gamma former by increase of Ni content. Differential scanning calorimetry (DSC) measurements also revealed that the gamma' solvus temperature increases with Ni content, while the solidus temperature is hardly affected by such content. The lattice parameter of the gamma and gamma' phases and the mismatch decreased with increasing Ni content, which caused the morphologic change of the gamma' precipitates from cubes to spheres.