Assessing efficacy of standard impregnation techniques on die-cast aluminum alloys using X-ray micro-CT

Utilizing lightweight Al alloys in various industrial applications requires achieving precise pressure tightness and leak requirements.Vacuum pressure impregnation(VPI)with thermosetting polymers is commonly used to address leakage defects in die-cast Al alloys.In this study,the efficacy of the VPI technique in sealing alloy parts was investigated using a combination of nondestructive micro X-ray computed tomography(micro XCT)and a standard leak test.The results demonstrate that the commonly used water leak test is insufficient for determining the sealing performance.Instead,micro XCT shows distinct advantages by enabling more comprehensive analysis.It reveals the presence of a low atomic number impregnates sealant within casting defects,which has low grey contrast and allows for visualizing primary leakage paths in 3D.The effective atomic number of impregnated resin is 6.75 and that of Al alloy is 13.69 by dual-energy X-ray CT.This research findings will contribute to enhancing the standard VPI process parameters and the properties of impregnating sealants to improve quality assurance for impregnation in industrial metals.

Additive Manufacturing of Metal Micro-ring and Tube by Laser-Assisted Electrophoretic Deposition with Laguerre-Gaussian Beam

We report a method for laser-assisted electrophoretic deposition using a Laguerre-Gaussian beam for maskless patterning of metal rings and tubes.These are structures of utmost importance,particularly in photonic devices.Metal nanoparticles,which are gathered in a colloidal solution by a laser trapping technique,are deposited on a substrate via electrophoresis.The deposition pattern is dependent on the focused spot shape during laser trapping.The intensity distribution of the Laguerre-Gaussian beam is ring-shaped.Rings with different inner diameters can be fabricated by varying the topological charge of the Laguerre-Gaussian beam.The equivalent inner diameters of the deposited rings with topological charges of 1,3,and 5 were 0.30,0.78,and 1.45μm,respectively.The inner diameter of the deposited ring with a topological charge of 1 was smaller than the wavelength of the laser beam(532 nm).A tube was also fabricated with a topological charge of 3 by vertical displacement of the deposition cell.The deposition technology developed here using Laguerre-Gaussian beam will contribute to advancements in the fabrication of photonic and nano-fluidic devices.