Probability of Detection and Defect Distribution Modeling of Porous Hard-Alpha Inclusions in Titanium Aero-Engine...

Area of Science:

• Materials Science and Engineering
• Non-Destructive Testing
• Metallurgy

Background:

• Hard-alpha inclusions in titanium alloys pose a significant risk to aero-engine disk integrity.
• Previous research often used synthetic dense particles, overlooking differences with real porous inclusions.
• The scarcity of natural inclusions hinders accurate defect characterization.

Purpose of the Study:

• To fabricate realistic porous hard-alpha inclusions in TC4 titanium alloy.
• To investigate the ultrasonic non-destructive testing characteristics of these inclusions.
• To develop a probability of detection (POD) model and a defect distribution model for probabilistic damage tolerance assessment.

Main Methods:

• Introduction of titanium nitride sponge preforms during electrode preparation for smelting.
• Fabrication of real porous hard-alpha inclusions in TC4 titanium alloy disks.
• Ultrasonic non-destructive testing and data analysis to establish POD and defect distribution models.

Main Results:

• Successfully fabricated real porous hard-alpha inclusions in TC4 titanium alloy.
• Established the first POD model for porous hard-alpha inclusions.
• Derived a novel defect distribution model exhibiting a cubic polynomial relationship, differing from traditional linear models.

Conclusions:

• The novel fabrication method yields realistic porous hard-alpha inclusions.
• The developed POD and defect distribution models enhance the assessment of titanium alloy integrity.
• The cubic polynomial defect distribution model offers a more accurate representation for probabilistic damage tolerance assessments.