Metallographic investigation of the microstructure and structure stability in high temperature nickel-base alloys Final report

Aim of this project is to optimize heat treatments to reveal a microstructure for improved material properties. The developed heat treatments should give an optimum combination of the different material properties for the application to steam turbine bolts. The influence of a previous cold working as well as different heat treatments on the microstructure are investigated for the materials Nimonic 70, Nimonic 80A and Inconel X-750. The measurement of different material data (hardness, thermal expansion coefficient, impact thoughness) as well as creep and relaxation tests show the material behavior according to the different microstructures. (orig.)SIGLEAvailable from TIB Hannover: RO 9714(12)+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany)DEGerman