Benzing J T, Liew L A, Hrabe N, DelRio F W
Applied Chemicals and Materials Division, National Institute of Standards and Technology, 325 Broadway, MS-647 Boulder CO 80305 USA.
Exp Mech. 2019;60(2). doi: https://doi.org/10.1007/s11340-019-00558-4.
The commercialization of additive manufacturing (AM) is underway in the aerospace and biomedical device industries [1, 2]. However, most metal parts produced by AM are limited to non-critical applications, since the various processes produce internal porosity, anisotropy, and microstructural heterogeneities [1, 3]. It has been implied that small-scale mechanical tests can advance measurement standards for AM applications by probing the effects of defects and heterogeneities on mechanical properties at more appropriate length scales [4, 5]. Traditionally, small-scale techniques have been used to characterize location- and orientation-specific mechanical properties in wrought materials [6-10]. A common method for excising mechanical test specimens from bulk parts with negligible influence on specimen integrity involves electrical discharge machining (EDM) [11]. This work demonstrates that excising meso-scale tensile specimens from additively manufactured parts enables tracking of sub-surface and visible features of interest (porosity and microstructural heterogeneities) throughout the entire gauge section such that the individual contributions to deformation behavior can be assessed.
增材制造（AM）正在航空航天和生物医学设备行业中实现商业化[1,2]。然而，由于各种工艺会产生内部孔隙率、各向异性和微观结构不均匀性，增材制造生产的大多数金属零件仅限于非关键应用[1,3]。有人认为，小规模机械测试可以通过在更合适的长度尺度上探究缺陷和不均匀性对机械性能的影响，从而推进增材制造应用的测量标准[4,5]。传统上，小规模技术已被用于表征锻造材料中特定位置和方向的机械性能[6-10]。一种从大块零件中切除机械测试试样且对试样完整性影响可忽略不计的常用方法是电火花加工（EDM）[11]。这项工作表明，从增材制造零件中切除中尺度拉伸试样能够在整个标距段跟踪感兴趣的亚表面和可见特征（孔隙率和微观结构不均匀性），从而可以评估它们对变形行为的各自贡献。
