Additive manufacturing (AM) can create net or near-net-shaped components while simultaneously building the material microstructure, therefore closely coupling forming the material and shaping the part in contrast to traditional manufacturing with distinction between the two processes. While there are well-heralded benefits to AM, the widespread adoption of AM in fatigue-limited applications is hindered by defects such as porosity resulting from off-nominal process conditions. The vast number of AM process parameters and conditions make it challenging to capture variability in porosity that drives fatigue design allowables during qualification. Furthermore, geometric features such as overhangs and thin walls influence local heat conductivity and thereby impact local defects and microstructure. Consequently, qualifying AM material within parts in terms of material properties is not always a straightforward task. This article presents an approach for rapid qualification of AM fatigue-limited parts and includes three main aspects: (1) seeding pore defects of specific size, distribution, and morphology into AM specimens, (2) combining non-destructive and destructive techniques for material characterization and mechanical fatigue testing, and (3) conducting microstructure-based simulations of fatigue behavior resulting from specific pore defect and microstructure combinations. The proposed approach enables simulated data to be generated to validate and/or augment experimental fatigue data sets with the intent to reduce the number of tests needed and promote a more rapid route to AM material qualification. Additionally, this work suggests a closer coupling between material qualification and part certification for determining material properties at distinct regions within an AM part.

增材制造 (AM) 可以在构建材料微观结构的同时创建净形或近净形部件，因此与传统制造相比，材料成形和零件成形紧密耦合，两种工艺之间存在区别。尽管增材制造具有广为人知的优点，但增材制造在疲劳限制应用中的广泛采用受到非标称工艺条件导致的孔隙率等缺陷的阻碍。大量的增材制造工艺参数和条件使得捕获孔隙率的变化变得具有挑战性，而孔隙率在鉴定过程中会驱动疲劳设计的允许。此外，悬垂和薄壁等几何特征会影响局部导热率，从而影响局部缺陷和微观结构。因此，根据材料特性对零件内的增材制造材料进行鉴定并不总是一项简单的任务。本文提出了一种快速鉴定增材制造疲劳极限零件的方法，包括三个主要方面：(1) 将特定尺寸、分布和形态的孔隙缺陷植入增材制造样品中，(2) 将材料的非破坏性和破坏性技术相结合表征和机械疲劳测试，(3) 对特定孔隙缺陷和微观结构组合产生的疲劳行为进行基于微观结构的模拟。所提出的方法能够生成模拟数据来验证和/或增强实验疲劳数据集，旨在减少所需的测试数量并促进更快速地获得增材制造材料资格。此外，这项工作建议材料鉴定和零件认证之间更紧密地结合，以确定增材制造零件内不同区域的材料属性。