Evaluation of a Modified Void Descriptor Function to Uniquely Characterize Pore Networks and Predict Fracture-Related Properties in Additively Manufactured Metals
Evaluation of a Modified Void Descriptor Function to Uniquely Characterize Pore Networks and Predict Fracture-Related Properties in Additively Manufactured Metals
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DOI：
10.1016/j.actamat.2021.117464
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发表时间：
2021-11
期刊：
影响因子：
9.4
通讯作者：
Dillon Watring;J. Benzing;O. L. Kafka;L. Liew;Newell Moser;J. Erickson;N. Hrabe;A. Spear
中科院分区：
文献类型：
--
作者：
Dillon Watring;J. Benzing;O. L. Kafka;L. Liew;Newell Moser;J. Erickson;N. Hrabe;A. Spear
增材制造（AM）工艺参数之间的细微差异导致孔隙网络的变化，并使对空隙敏感的机械行为（包括断裂位置）的预测变得复杂。目前的工作扩展后，最近开发的孔隙度，空隙描述符功能（VDF），通过考虑相邻的孔隙和应力集中引起的非球形孔隙或空隙之间的相互作用。修改后的VDF进行评估，对120计算生成的断裂模拟和六个物理拉伸试样的建成激光粉末床熔融IN 718。后一组实验，其中包括变形前后的X射线计算机断层扫描测量，使评价对孔隙人口的缺陷，通常在AM金属中观察到的代表。修改后的VDF准确预测了120个模拟样本中94个样本的断裂位置（在±5%公差范围内），与基于原始VDF、最大横截面积减少位置和最大孔隙位置的预测相比，准确预测数量分别增加了3.3%、62.1%和59.3%。在实验数据集中，修改后的VDF准确地预测了六个样本中的五个样本的断裂位置，而使用原始VDF、最大横截面积减少或最大孔隙位置的六个样本中只有两个样本的断裂位置。此外，发现改性VDF的最大值比孔隙率分数、孔径、缩小横截面积和孔隙总数与极限拉伸强度、断裂延伸率和韧性模量的相关性更高，这表明，在这项工作中提出的修改后的VDF可以作为一个有前途的指标，以帮助表征独特的孔隙网络和预测裂缝-AM组件中的相关属性。
Subtle differences among additive manufacturing (AM) processing parameters lead to variations in pore networks and complicate the prediction of void-sensitive mechanical behaviors, including location of fracture. The current work expands upon a recently developed pore metric, the void descriptor function (VDF), by accounting for interactions among neighboring pores and stress concentrations induced by non-spherical pores or voids. The modified VDF is evaluated against 120 computationally generated fracture simulations and six physical tensile specimens of as-built laser powder bed fused IN718. The latter set of experiments, which include X-ray computed tomography measurements before and after deformation, enables evaluation against pore populations that are representative of defects commonly observed in AM metals. The modified VDF accurately predicts fracture location (within±5% tolerance) for 94 out of 120 simulated specimens, representing 3.3%, 62.1%, and 59.3% increases in the number of accurate predictions in comparison to predictions based on the original VDF, the location of maximum cross-sectional area reduction, and the largest-pore location, respectively. In the experimental data set, the modified VDF accurately predicts the location of fracture in five out of six specimens compared to only two out of six using the original VDF, maximum cross-sectional area reduction, or largest-pore location. Also, the maximum value of the modified VDF was found to be more highly correlated than fraction porosity, pore size, reduced-cross section area, and total number of pores to the ultimate tensile strength, elongation to failure, and toughness modulus, suggesting that the modified VDF presented in this work could serve as a promising metric to assist with characterizing unique pore networks and predicting fracture-related properties in AM components.