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Inducing Known, Controlled Flaws in Electron Beam Wire Fed Additive Manufactured Material for the Purpose of Creating Non-Destructive Inspection Standards

Description:

Several military platforms are targeting EBAM for production of new, replacement, and repair components. Standard NDI methods are currently being applied to EBAM components, but significant capability gaps exist in inspections of component preforms thicker than approximately 3". Uncertainty remains around the probability of detection, minimum detectable flaw size, and resolution of non-destructive inspections (NDI) on typical flaws found in additive manufacturing (AM) materials. Improved standards are needed to down select and optimize specific NDI techniques (X-ray, computed tomography (CT), and ultrasound (UT)) for these components. Typical NDI standards for X-ray, CT, and UT inspection consist of a block of material fashioned to a representative shape and thickness to represent the component to be inspected. Representative flaws are introduced by drilling side-drilled and/or flat bottomed holes and/or burning electric discharge machining (EDM) notches into the standard. These flaws do not always adequately represent volumetric flaws within a component, particularly with methods such as CT. A novel method to induce known, controlled flaws in EBAM materials for production of improved NDI standards offers the promise of increased confidence and reliability in these inspections. PHASE I: Determine and demonstrate feasibility to develop reliable and repeatable methods for inducing known, controlled flaws representative of porosity, lack of fusion, and cracking due to residual stresses in Ti-6Al-4V samples deposited by EBAM. Demonstrate the feasibility of applying at least one such approach by fabricating and inspecting coupon specimens. PHASE II: Provide practical implementation of a production-scalable process to implement the recommended approach developed under Phase I. Evaluate the approach through the fabrication and evaluation of a sufficient quantity of NDI test coupons. Develop and fabricate an NDI standard using the recommended method utilizing relevant specifications as cited in the references and Government defined flaw geometries (minimum flaw size will nominally be 0.0500 in. +/- 0.0005 in.). PHASE III: Transition the NDI standard manufacturing approach to military aircraft component fabricators and commercial industry which utilize EBAM for new, replacement, or repair components.
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