| Abstract Scope |
The aero-engine community has continued to collectively identify and work on activities for continuous improvement of product safety. The Federal Aviation Administration (FAA) published Advisory Circular (AC) 33.15-1 (Manufacturing Process of Premium Quality Titanium Alloy Rotating Engine Components) is one tool in this industry-wide initiative. The industry is making recommendations to the FAA to update this document to include learnings regarding the multiple potential root causes of cold-dwell fatigue failures. In particular, perspectives relative to critical process and product features are discussed as they pertain to the formation of microtexture, a major contributing element for this mechanism. Parameters that influence the formation of microtexture in titanium billet and forgings, such as alloy chemistry, beta grain size control, beta transformation structure and alpha-beta strain path are outlined as part of the industry-wide recommendations to FAA for inclusion in an update to AC 33.15-1. Best practices and considerations are included in the recommended update, which help guide material, process and product development, and application for the avoidance of potential future cold-dwell fatigue failures in titanium alloy critical rotating parts. |