PDF(Pubmed)
Abstract：
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.
摘要：
增材制造（AM）可以创建网状或接近网状的组件，同时构建材料的微观结构。因此，与传统制造相比，紧密耦合形成材料和成形零件，这两种工艺之间有区别。虽然AM有众所周知的好处，AM在疲劳受限应用中的广泛采用受到诸如非标称工艺条件导致的孔隙度等缺陷的阻碍。大量的AM工艺参数和条件使得捕获孔隙率的可变性具有挑战性，这在鉴定期间驱动疲劳设计允许。此外，几何特征，如悬垂和薄壁影响局部热导率，从而影响局部缺陷和微观结构。因此,根据材料特性来限定零件内的AM材料并不总是一项简单的任务。本文提出了一种快速鉴定AM疲劳受限零件的方法，包括三个主要方面：（1）播种特定尺寸的孔隙缺陷，分布，和形态学到AM标本中，（2）结合无损和破坏性技术进行材料表征和机械疲劳测试，和（3）进行基于微观结构的模拟疲劳行为产生的特定的孔缺陷和微观结构的组合。所提出的方法能够生成模拟数据以验证和/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的AM材料鉴定。此外,这项工作表明材料鉴定和零件认证之间的更紧密耦合，以确定AM零件内不同区域的材料性能。
