Abstract:Thanks to its advantages of high efficiency and near-net shaping, laser directed energy deposition (LDED) is rapidly becoming a remarkable preparation technology for high-purity ceramics. However, the cracking problem in shaping process is always a great challenge for LDED to achieve industrial application. For this purpose, alumina/aluminum titanate melt-growth ceramics (A/AT MGCs) were prepared using LDED system, and the corresponding finite element thermal analysis model was developed. The solidification be… Show more
“…Processing parameter optimization serves as a convenient and fundamental approach to control cracks via modifying both local thermal conditions and microstructures [182]. Also, it lays the groundwork for further implementing other strategies to suppress defects, such as field-assisted dAM techniques and secondary-phase toughening [77].…”
Section: Crack Suppression Methodsmentioning
confidence: 99%
“…Through analyzing the influence of laser power, scan speed, and scanning strategy on simulated temperature distributions, the optimal laser parameters for single-layers shaping can be determined. Huang et al [174,182] further advanced the understanding of dAM processes by developing a thermal-mechanical coupled FEM model to analyze the dynamic temperature evolution and thermal stress distribution in L-DEDed Al 2 O 3 -TiO 2 thin-walled structures (figures 17(b) and (c)). This enabled them to elucidate the crack formation mechanism in dAMed specimens, revealing a strong correlation between crack patterns, local thermal stress, and microstructure.…”
Ceramic oxides, renowned for their exceptional combination of mechanical, thermal, and chemical properties, are indispensable in numerous crucial applications across diverse engineering fields. However, conventional manufacturing methods frequently grapple with limitations, such as challenges in shaping intricate geometries, extended processing durations, elevated porosity, and substantial shrinkage deformations. Direct additive manufacturing (dAM) technology stands out as a state-of-the-art solution for ceramic oxides production. It facilitates the one-step fabrication of high-performance, intricately designed components characterized by dense structures. Importantly, dAM eliminates the necessity for post-heat treatments, streamlining the manufacturing process and enhancing overall efficiency. This study undertakes a comprehensive review of recent developments in dAM for ceramic oxides, with a specific emphasis on the laser powder bed fusion and laser directed energy deposition techniques. A thorough investigation is conducted into the shaping quality, microstructure, and properties of diverse ceramic oxides produced through dAM. Critical examination is given to key aspects including feedstock preparation, laser–material coupling, formation and control of defects, in-situ monitoring and simulation. This paper concludes by outlining future trends and potential breakthrough directions, taking into account current gaps in this rapidly evolving field.
“…Processing parameter optimization serves as a convenient and fundamental approach to control cracks via modifying both local thermal conditions and microstructures [182]. Also, it lays the groundwork for further implementing other strategies to suppress defects, such as field-assisted dAM techniques and secondary-phase toughening [77].…”
Section: Crack Suppression Methodsmentioning
confidence: 99%
“…Through analyzing the influence of laser power, scan speed, and scanning strategy on simulated temperature distributions, the optimal laser parameters for single-layers shaping can be determined. Huang et al [174,182] further advanced the understanding of dAM processes by developing a thermal-mechanical coupled FEM model to analyze the dynamic temperature evolution and thermal stress distribution in L-DEDed Al 2 O 3 -TiO 2 thin-walled structures (figures 17(b) and (c)). This enabled them to elucidate the crack formation mechanism in dAMed specimens, revealing a strong correlation between crack patterns, local thermal stress, and microstructure.…”
Ceramic oxides, renowned for their exceptional combination of mechanical, thermal, and chemical properties, are indispensable in numerous crucial applications across diverse engineering fields. However, conventional manufacturing methods frequently grapple with limitations, such as challenges in shaping intricate geometries, extended processing durations, elevated porosity, and substantial shrinkage deformations. Direct additive manufacturing (dAM) technology stands out as a state-of-the-art solution for ceramic oxides production. It facilitates the one-step fabrication of high-performance, intricately designed components characterized by dense structures. Importantly, dAM eliminates the necessity for post-heat treatments, streamlining the manufacturing process and enhancing overall efficiency. This study undertakes a comprehensive review of recent developments in dAM for ceramic oxides, with a specific emphasis on the laser powder bed fusion and laser directed energy deposition techniques. A thorough investigation is conducted into the shaping quality, microstructure, and properties of diverse ceramic oxides produced through dAM. Critical examination is given to key aspects including feedstock preparation, laser–material coupling, formation and control of defects, in-situ monitoring and simulation. This paper concludes by outlining future trends and potential breakthrough directions, taking into account current gaps in this rapidly evolving field.
“…To detect the cracks in bulks sample, the Al 2 O 3 –ZrO 2 samples were colored, penetrated, and developed with DPT‐8 colored penetrant flaw detector 33 and observed using a low‐power optical microscope. The crack density ( D ) that is defined as the ratio of the crack total length ( l ) to the cross‐sectional area ( A ) 36 were calculated under each bulk samples, through four pictures: …”
The cracks in Al2O3–ZrO2 eutectic ceramics produced by laser powder bed fusion (LPBF) have a significant impact on their practical applications in various industries. In order to understand the factors influencing crack formation, a systematic study of the characterization and propagation of cracks in single‐track, multi‐track, and bulk samples by varying the process parameters has been carried out in this research. The results showed that parallel cracks can be healed by reducing the scanning spacing and scanning length. Additionally, it was found that using a modest scanning speed and a shorter length can minimize the accumulation of thermal stress, resulting in the suppress crack formation. Based on this conclusion, a crack‐free Al2O3–ZrO2 eutectic ceramic sample was finally obtained under the optimized parameters with the power of 100 W, the scanning speed of 100 mm/s, the hatch spacing of 100 μm, the scanning length of 3 mm, and the layer thickness of 50 μm. Additionally, three typical microstructures, including eutectic, cellular, and dendritic structures, were identified in the LPBF‐fabricated Al2O3–ZrO2 samples. The cellular microstructure showed improved crack inhibition capability due to the deflection and pinning effects. Cracks expand more easily in dendritic and eutectic microstructures, where anisotropy is more prominent.
“…As a result of their dense internal microstructures and particle refining, shaped samples with a high melting‐cooling rate (10 3 –10 5 K/s) have outstanding properties 18 . LDED is now being widely applied and researched in the fabrication of melt‐growth ceramics 19–31 . It is feasible to integrate different materials, which greatly enhances the flexibility in material design.…”
Section: Introductionmentioning
confidence: 99%
“…18 LDED is now being widely applied and researched in the fabrication of melt-growth ceramics. [19][20][21][22][23][24][25][26][27][28][29][30][31] It is feasible to integrate different materials, which greatly enhances the flexibility in material design. This approach is not limited by the size of components, making it particularly suitable for manufacturing composites and functional graded materials.…”
Functionally graded ceramics (FGCs), which combine the properties of various composite ceramics, have been widely used in the aerospace, armament, and other industries. One of the newest melt‐growth ceramic additive manufacturing techniques, laser directed energy deposition (LDED), enables the creation of gradient materials by controlling the ratio of powder delivery. Ceramic–ceramic type gradient materials are the subject of fewer studies, and the majority of LDED gradient material systems now in research are metal–metal type and metal–ceramic type gradient materials. In this paper, LDED is used to create TiCp reinforced Al2O3 FGCs with three different transition paths. The results indicate that the longitudinal section of the gradient samples distinctly exhibits characteristics of gradient distribution. Furthermore, as the proportion of TiCp increases, there is a corresponding increase in the proportion of TiCp particles in the samples. The microstructure of Al2O3 transforms from columnar crystals to irregular shapes. Regarding the mechanical properties of the gradient samples, the area containing 30 wt.% of TiCp shows a significant improvement in wear resistance, with a 48.13% increase compared to the Al2O3 region. Additionally, this region demonstrates a 12.62% rise in hardness and a 9.48% increase in fracture toughness.
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