Microstructure, Lattice Misfit, and High-Temperature Strength of gamma '-Strengthened Co-Al-W-Ge Model Superalloys

作者：Zenk Christopher H^*; Bauer Alexander; Goik Philip; Neumeier Steffen; Stone Howard J; Goeken Mathias

来源：Metallurgical and Materials Transactions A-Physical Metallurgy and Materials Science, 2016, 47A(5): 2141-2149.

DOI：10.1007/s11661-016-3408-8

The quaternary alloy system Co-Al-W-Ge was investigated and it was found that a continuous gamma/gamma' two-phase field extends between the systems Co-Al-W and Co-Ge-W. All alloys examined comprised cuboidal L1(2) precipitates coherently embedded in an A1 matrix. Differential scanning calorimetry measurements revealed that the liquidus, solidus, and gamma'-solvus temperatures decrease when the Ge content is increased. The lower liquidus temperature and the capability of gamma'-strengthening in the Ge-rich alloys make them interesting as potential candidates for brazing applications of Co-base superalloys. The gamma/gamma' lattice misfit was determined by high-resolution X-ray diffraction and found to be positive for all alloys investigated, decreasing with increasing Ge content. The mechanical properties of the Al-rich alloys surpass those rich in Ge.

• 出版日期2016-5