Developments in The Production of Oxide Dispersion Strengthened Superalloys

Abstract

Developments in the production of prealloyed oxide dispersion strengthened superalloy powders have resulted in the commercial scaling-up of the mechanical alloying process. This method incorporates a uniform dispersion of yttrium oxide particles of 20–40 nm dia. into superalloy base compositions and effectively extends the maximum temperature capabilities of such alloys by several hundred degrees kelvin. Powder metallurgical consolidation techniques and controlled thermo-mechanical working processes are required to achieve optimum properties in a range of commercial alloys and product forms. One of the alloys, Inconel alloy MA 6000, is an advanced turbine blade material strengthened by solid solution additions, γ′, and yttrium oxide compounds. A zone annealing technique is used to achieve a highly directional coarse grain structure which further enhances creep resistance. In addition to components in the hot section of gas turbines, Inconel alloy MA 754 and Incoloy alloy MA 956 now are found in a wide range of high temperature general engineering applications. PM/0286