On the development of low mass density gamma strengthened Co-based superalloys
The work herein aims at developing new class of low mass density gamma-strengthened Co-based superalloys with good solvus temperature through systematic addition of Cr into the Co-Ni-Al- Mo-Ta based superalloy. The present thesis is divided into six chapters. The first chapter introduces various superalloys (Ni, Co and Fe-based) for high temperature applications. The timeline of different generations of Ni-based superalloys along with development in melting and casting techniques have been discussed in this chapter. All the gamma strengthened Co-based superalloys that are developed till date, and the effect of various alloying additions on the gamma stability in these alloys have also been summarized. Finally, the aims and objectives of the present thesis are defined. In the second chapter, the experimental methods are outlined. The experimental results and discussion are presented in the three subsequent chapters.