Abstract
Metal-based additive manufacturing (AM) is a disruptive technique with great potential across multiple industries; however, its manufacturing quality is unstable, leading to an urgent requirement for component properties detection. The distribution of grain size has an important effect on many mechanical properties in AM, while the distribution of added elements, such as titanium (Ti), has a measurable effect on the grain size of an aluminum (Al) alloy. Therefore, the detection of the distributions of grain size and elements is of great significance for AM. In this study, we investigated the distribution of grain size and elements simultaneously for wire + arc additive manufacturing (WAAM) with an Al alloy using laser opto-ultrasonic dual (LOUD) detection. The average grain size obtained from the acoustic attenuation of ultrasonic signals was consistent with the results of electron backscatter diffraction (EBSD), with a coefficient of determination (R2) of 0.981 for linear fitting. The Ti element distribution obtained from optical spectra showed that the enrichment of Ti corresponded to the grain refinement area in the detected area. The X-ray diffraction (XRD) spectra showed that the spectral peaks were moved from Al to AlTi and Al2Ti forms in the Ti-rich areas, which confirmed the LOUD results. The results indicated that LOUD detection holds promise for becoming an effective method of analyzing the mechanical and chemical properties of components simultaneously, which could help explain the complex physical and chemical changes in AM and ultimately improve the manufacturing quality.
Highlights
As a disruptive technique with great potential across multiple industries, additive manufacturing (AM) has been developed in the energy, aerospace, and biomedical industries [1]
The measured data of the grain size distribution determined from the electron backscatter diffraction (EBSD) maps were plotted as red histograms in Figure 4b, which shows the proportion of grains with different sizes in the total grains
Based on Equation 3, the measured data of the acoustic attenuation coefficient from laser opto-ultrasonic dual (LOUD) detection were plotted as blue histograms in Figure 4c, which shows the proportion of different attenuation coefficients in the total detection results
Summary
As a disruptive technique with great potential across multiple industries, additive manufacturing (AM) has been developed in the energy, aerospace, and biomedical industries [1]. The distribution of grain size in components has been investigated for its connection to porosity [2] as well as most mechanical properties, such as stress, hardness, and tensile strength [3,4,5,6,7]. The methods of grain size detection are mainly divided into two types: destructive and nondestructive. Destructive detection methods, such as optical metallography and electron backscatter diffraction (EBSD) [9,10], are limited in engineering. Their shortcomings include the fact that they are time consuming, that they involve microdetection, and that they result in irreversible damage to the material. Nondestructive detection, including the eddy current method [11], the magnetic
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