In order to meet the airworthiness requirements

a method for obtaining material defect (hard α inclusions) distribution data of typical titanium alloy was explored. According to the theoretical model of titanium alloy disk manufacturing process

the defect distribution baseline was acquired

using the detected defect distribution and the probability of detection(POD) of nondestructive test in the manufacturing process. The programs of POD test and microsection test

which meet the airworthiness requirements

were proposed. The key test technologies were determined to obtain POD curve and detected defects data

including specimen specifications

nitrogen mass fraction and distribution of hard alpha inclusions

ultrasonic test standard

steps of microsection

etc. Then

the exceedance curve of defect distribution was acquired by the use of theoretical deduction and logarithm linear fitting. The characteristics of material defects and airworthiness requirment were determines

then a method of obtaining POD curve and defect distribution curve was put forword.The method provides inputs for probabilistic risk assessment on aero-engine disk

supporting the airworthiness forensics of aero-engine disk.