Rapid, Local Characterization of the Fatigue Crack Growth Behavior

ABSTRACT: The current Phase I program is focused on the development of an affordable test method to extract local crack growth data for cracks propagating through Microtexture Regions (MTRs) occurring within a titanium material, and to assess the viability of the method for crack growth characterization.Per the solicitation, emphasis will be given to near-threshold cold dwell crack growth conditions where the crack tip constraint may be considered to be plane strain.Under these conditions, the crack growth acceleration due to the presence of MTRs is believed to be maximized.; BENEFIT: In Titanium, crack growth rates in MTRs are estimated to be 10x-100x that of the bulk material.This phenomenon has contributed to a number of turbine engine incidents over the past 40 years yet a great deal of uncertainty remains. Thus, a more detailed assessment of the impact of material texture and microtexture on material performance is required.In a broader context, it is anticipated that the methods developed herein could potentially find future use in quantifying local crack growth properties not only in MTRs, but other constituent particles of interest in multi-scale material model development.