Void distribution in a brazed cemented carbide steel joint analyzed by X-ray microscopy

Yared, Wadih; Chen, Chih-Yu; Sievers, Norman; Tillmann, Wolfgang; Zielke, R.; Schimpfermann, Max

doi:10.1016/j.measurement.2019.04.045

Cited by 14 publications

(8 citation statements)

References 14 publications

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“…The auxetic structural behavior measured by the conventional tensile testing machine illustrated a large deformation discrepancy between the upper as well as the lower rows and the middle three rows of the honeycombs. To achieve quantitative data for the analysis, in-situ CT tests with a combination of digital image correlation (DIC) are preferred, which allows for the calculation of the local displacement/strain maps [ 27 , 28 , 29 , 30 ]. A more detailed presentation of the CT test and DIC technique is shown in [ 27 , 28 , 29 , 30 ].…”

Section: Methodsmentioning

confidence: 99%

Deformation Behavior of 3D Printed Auxetic Structures of Thermoplastic Polymers: PLA, PBAT, and Blends

et al. 2023

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Auxetic structures have a negative Poisson’s ratio and therefore expand transversely to the direction of loading instead of tapering. This unique behavior is not caused by the materials used, but by the structure, and thus offers completely new functionalities and design possibilities. As a rule, auxetic structures have a very complex geometry, which makes cost-effective production possible only by means of additive manufacturing processes. Due to the high design freedom of the strand deposition method, it makes sense to manufacture auxetic structures using this process. Therefore, in this project, polylactide acid (PLA), polybutylene adipate terephthalate (PBAT), and blends of the two polymers were produced and characterized. Filaments of the two polymers and a blend were extruded, processed into auxetic structures by strand deposition process (SDP), and investigated for their properties, primarily their Poisson’s ratio. The Poisson’s ratio was determined and the influence of the material on it was identified. A specific number of 5 × 5 unit cells has been found to be ideal for investigation. Dual printed specimens showed a similar auxetic behavior as the specimens made of pure PBAT. Likewise, multiple loading and unloading of the structure is possible. Furthermore, in-situ computed tomography revealed the detailed characterization of the initial state, including the warpage of the structures, damage, and traced auxetic behavior in detail.

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Section: Methodsmentioning

confidence: 99%

Deformation Behavior of 3D Printed Auxetic Structures of Thermoplastic Polymers: PLA, PBAT, and Blends

et al. 2023

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“…In some cases, voids formation may be the result of the inability of sufficient removal of flux (in the BFM) from the thin braze joint. 21 Hence, it is recommended to strictly avoid the sources of void formation during the brazing operation. It is noted in area 1 that the oxygen content in sapphire is insufficient to be matched with Al (see Figure 7).…”

Section: Resultsmentioning

confidence: 99%

“…Besides the temperature factor, other sources of voids include surface contamination, base metal and BFM constituents, poor joint fit-up, and so on. In some cases, voids formation may be the result of the inability of sufficient removal of flux (in the BFM) from the thin braze joint . Hence, it is recommended to strictly avoid the sources of void formation during the brazing operation.…”

Section: Resultsmentioning

confidence: 99%

Analysis of the Reaction Layer Formed during Sapphire–Sapphire Brazing Using a Ag–Cu–Ti Filler Metal for Gas-Pressure Sensors

Zaharinie

Huda

Ibrahim

et al. 2022

ACS Appl. Electron. Mater.

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The present research paper introduces a reliable and economical method for direct brazing using an active Ag−Cu−Ti filler metal that can ensure effective brazing. The sapphire−sapphire brazing process has been conducted at temperatures in the range of 830−900 °C for durations in the range of 15−30 min in a high-vacuum (10 −4 Pa) furnace. Material and microstructural characterization involved the use of scanning electron microscope-energy-dispersive system (SEM-EDS) and transmission electron microscope (TEM) for investigating the bonding joint morphologies. Two uniform reaction layers were observed to have formed at the sapphire/brazed area interface. On the sapphire side, the first reaction layer, which was uniform and had a thickness in the range of 0.13−0.17 μm, was identified as a TiO phase, whereas the second layer was identified as a Cu 3 Ti 3 O phase with a thickness in the range of 1.72−2.43 μm. The uniformity of the Cu 3 Ti 3 O phase was found to decrease with increasing brazing temperature and time. Therefore, in this research, a lower brazing temperature and time (830 °C/15 min) were chosen so as to avoid bonding degradation.

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“…Results of the SAM inspection of hard and elastic materials Figure 4 demonstrates the adhesive composite structure between tungsten carbide and the shank with variations in the adhesive layer thickness. The composite bites bonded with epoxy are widely used in high performance cutting parts of automatic lathes and micromechanics (Yared et al 2019). The performance characteristics of the carbide are determined by the hardness, transverse rupture strength and fracture toughness.…”

Section: Methodsmentioning

confidence: 99%

Scanning acoustic microscopy for material evaluation

2020

Appl. Microsc.

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Scanning acoustic microscopy (SAM) or Acoustic Micro Imaging (AMI) is a powerful, non-destructive technique that can detect hidden defects in elastic and biological samples as well as non-transparent hard materials. By monitoring the internal features of a sample in three-dimensional integration, this technique can efficiently find physical defects such as cracks, voids, and delamination with high sensitivity. In recent years, advanced techniques such as ultrasound impedance microscopy, ultrasound speed microscopy, and scanning acoustic gigahertz microscopy have been developed for applications in industries and in the medical field to provide additional information on the internal stress, viscoelastic, and anisotropic, or nonlinear properties. X-ray, magnetic resonance, and infrared techniques are the other competitive and widely used methods. However, they have their own advantages and limitations owing to their inherent properties such as different light sources and sensors. This paper provides an overview of the principle of SAM and presents a few results to demonstrate the applications of modern acoustic imaging technology. A variety of inspection modes, such as vertical, horizontal, and diagonal cross-sections have been presented by employing the focus pathway and image reconstruction algorithm. Images have been reconstructed from the reflected echoes resulting from the change in the acoustic impedance at the interface of the material layers or defects. The results described in this paper indicate that the novel acoustic technology can expand the scope of SAM as a versatile diagnostic tool requiring less time and having a high efficiency.

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Void distribution in a brazed cemented carbide steel joint analyzed by X-ray microscopy

Cited by 14 publications

References 14 publications

Deformation Behavior of 3D Printed Auxetic Structures of Thermoplastic Polymers: PLA, PBAT, and Blends

Deformation Behavior of 3D Printed Auxetic Structures of Thermoplastic Polymers: PLA, PBAT, and Blends

Analysis of the Reaction Layer Formed during Sapphire–Sapphire Brazing Using a Ag–Cu–Ti Filler Metal for Gas-Pressure Sensors

Scanning acoustic microscopy for material evaluation

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