Investigation of the Structure and Properties of the Ni3Al-Ni3Cb Eutectic Alloy.
Final rept. 1 Jul 68-31 Jul 69,
UNITED AIRCRAFT RESEARCH LABS EAST HARTFORD CT
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When unidirectionally solidified at rates below 3 cmhr, the Ni3Al gamma-Ni3Cb delta alloy grew with the eutectic phases as alternating lamellae aligned parallel to the direction of solidification. The lamellar phase morphology was examined by transmission electron microscopy, and the planes were found to exhibit preferred growth directions, 110 gamma and 100 delta parallel to the direction of solidification. The interfacial planes most commonly observed were -111 gamma parallel to 010 delta. The tensile properties of the eutectic were evaluated in the temperature range of 75 to 2200F and the creep and rupture properties in the temperature range of 1600 to 2200F. Its high temperature tensile and creep properties, measured in the direction of alignment, were found to be superior to all nickel base superalloys. The dynamic elastic modulus of the eutectic and its thermal expansion were measured from 75 to 1800F. The modulus was higher and the expansion lower than that which is typical for nickel base superalloys. Other properties of the eutectic which are reported include its notched tensile strength, the effect of interlamellar spacing on the strength, the temperature dependence of its impact properties, microhardnesses of the eutectic phases, compressive properties at room temperature, and oxidation behavior. Author
- Properties of Metals and Alloys
- Solid State Physics