Selective electron beam melting (SEBM) is an additive manufacturing process for the production of complex metallic parts. To optimize their mechanical properties, pores and fusion defects, since not completely avoidable, have to be detected and evaluated. The generated microstructure may contain not only voids, but also weak bonds, sharp interfaces and loose particles causing nonlinear elasticity. This paper reports on Nonlinear Impact Modulation Spectroscopy (NIMS) experiments applied to a set of Ti–6Al–4V samples, each of which contains an internal zone with well-defined porosity ranging from 0.2 to 20%, respectively. Resonance spectra, attenuation and indicators of material nonlinearity were evaluated, which allowed the localization, dimensioning and assessment of porous zones. Properties of used linear and nonlinear methods are discussed.

中文翻译：

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通过非线性冲击调制光谱法评估选择性电子束熔化制造的 Ti-6Al-4V 中的孔隙率

选择性电子束熔化 (SEBM) 是一种用于生产复杂金属零件的增材制造工艺。为了优化它们的机械性能，必须检测和评估气孔和熔合缺陷，因为不能完全避免。生成的微结构可能不仅包含空隙，还包含弱键、尖锐界面和导致非线性弹性的松散颗粒。本文报告了应用于一组 Ti-6Al-4V 样品的非线性冲击调制光谱 (NIMS) 实验，每个样品包含一个内部区域，其孔隙率分别为 0.2% 至 20%。对共振谱、衰减和材料非线性指标进行了评估，这使得多孔区域的定位、尺寸确定和评估成为可能。讨论了使用的线性和非线性方法的特性。