Castability of 718Plus® Alloy for Structural Gas Turbine Engine Components

Abstract

Recent developments from the cast 718Plus® Metals Affordability Initiative (MAI) program will be presented and discussed. The objective of the program is to investigate and enable the use of 718Plus® alloy in the form of investment castings by (1) increasing the allowable operating temperature by about 75°F as compared with conventional cast Alloy 718 and (2) achieve approximately 25 percent cost savings as compared with cast Waspaloy. This program builds on the successful MAI program for wrought 718Plus alloy. This technology will be implemented for the manufacture of gas turbine structural components including: combustor plenums, stator cases, diffuser cases, turbine cases, turbine frames, and other various high-strength/hightemperature structural castings. An overview of the results from the castability, weldability, and initial mechanical property investigations will be discussed. A preliminary cost benefit to aerospace components after implementation is predicted to be substantial. This recent work has warranted further investigation through the MAI program.718Plus® is a registered trademark of ATI Properties, Inc.