DIRECTIONALLY-SOLIDIFIED Co-Co7W6 EUTECTIC COMPOSITES FOR TURBINE BLADES | ||||
| International Conference on Aerospace Sciences and Aviation Technology | ||||
| Article 61, Volume 1, A.S.A.T. CONFERENCE 14-16 May 1985 r CAIRO, May 1985, Page 725-735 PDF (3.41 MB) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/asat.1985.26551 | ||||
 View on SCiNiTO | ||||
| Author | ||||
| Mohamed A. Taha | ||||
| Professor, Department of Design and Production Engineering, Faculty of Engineering, Ain-Shams University, Abbaseia, Cairo - EGYPT. | ||||
| Abstract | ||||
| Structural changes that arise due to growth rate variations in Co-Co7W6 directionally solidified eutectic composites have been observed* The growth rates (R)-considerd ranged from 1.38 to 55.5 pm/s. The temperature gradient was kept constant at an average value of 13±1 K/mm.The as-solidified structure, Nhich is produced by quenching from above the peritectoid temperature changes greately with R. At low R, aligned lamellar morphology is observed. The increase in R gradually causes perforatons, breaking into short ribbon-shape with width to thickness ratio decreasing with increasing R. Further increase in R causes first longitudinal branching in the ribbon plane, then the appearance of short side branches. At R. 55.5 pa/s the structure is cellular, each cell consisting of a single dendrite -like Co-Co7196 phase. Inspite of these variations in structure, the interlamellar or"inter-ribbon" spacing was found to obey the relationship K. nR 0. Further observations show the presence of faults in the steady-state grown structure. The peritectoid transformation which occurs in the Co matrix has no influence on the shape and dimensions of the Co7W6 phase. The addition of small solute elements of C,A1 and Cr promotes the cellular morphology both at high'and low R. | ||||
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