High Crack Research Articles

Study on the performance and mechanism of graphene oxide / polyurethane composite modified asphalt

In order to enhance the aging resistance, high temperature stability and low temperature crack resistance of asphalt pavement materials, 0.06% oxidized graphene (GO) and 12% polyurethane (PU) were used as composite modifiers to modify the base asphalt. The RTFOT test was conducted to evaluate the anti-aging performance of the modified asphalt. The rheological properties of GO/PU composite modified asphalt were evaluated. SEM and FTIR tests were used to analyze the microstructure of GO/PU modified asphalt. The results show that the basic performance of composite modified asphalt meets the requirements and the anti-aging performance is improved. The improvement of rutting factor and frequency scanning master curve shows its better anti-rutting deformation ability. The strain recovery R-value for the composite modified bitumen increased by 20.7% at a stress level of 0.1 kPa, and the unrecoverable creep compliance Jnr decreased by 76.0%, showing excellent viscoelastic properties. The creep stiffness S of composite modified asphalt decreased by 31.2% at−12 °C, indicating that it had good low temperature rheological properties. The surface of the modified composite asphalt is relatively smooth, exhibiting a stable network structure, thus solving the PU segregation problem in the matrix asphalt.The change of infrared spectrum absorption peak shows that reaction between isocyanate groups in polyurethane and aromatic esters in bitumen, GO oxidizes with the-CH functional group in asphalt, and the content of C = C double bond changes during the modification process, indicating that the modification of asphalt by GO and PU is a composite modification based on chemical modification and supplemented by physical modification.

Zirconia Post and Core Restorations: A Case Study Highlighting Exocad Laboratory Workflow and Material Review

Post and core buildups are important for damaged or endodontically stabilized teeth. Zirconia is a common material for these restorations due to its exceptional mechanical properties, biocompatibility, and aesthetic appeal. This study presents a case of a 47-year-old female patient, where the tooth was reconstructed and improved its appearance using zirconia bars and implants and was fabricated using Exocad software exactly as it was done in that process. Although zirconia offers impressive advantages, including durability and natural appearance, it presents challenges such as high cost and possible cracking risks. Studies establish how effective zirconia is at emphasizing the restoration of integrity while acknowledging its limitations.

Catalytic Pyrolysis of Moso Bamboo Over Acid‐treated Red Mud Catalyst for Bio‐Oil Production

AbstractRed mud (RM), one kind of waste from the alumina industry, was used to prepare 600‐RM catalyst and a series of xHCl‐RM catalysts. The catalytic pyrolysis of moso bamboo was conducted to evaluate the performance of the prepared catalysts. The 600‐RM catalyst showed a slight increase in the content of Fe, Al, Ca and Si, and a modest enlargement in pore volume and diameter. The xHCl‐RM catalysts exhibited well‐structured hierarchical porosity and enhanced specific surface area. After acid treatment, the contents of Fe, Al, and Si increased noticeably, with almost complete removal of Na and Ca. Thermal stability of the 600‐RM and xHCl‐RM catalysts was significantly improved compared to P‐RM. The results showed that the catalytic pyrolysis over 600‐RM enhanced high selectivity for phenols (59.81%, biomass/catalyst = 1/1 w/w) and alcohols (16.35%, biomass/catalyst = 1/1 w/w), facilitated by CaO promoting bond cleavage and free radical reactions. In addition, xHCl‐RM demonstrated enhanced activity for furans (23.11%) and carbonyl compounds (28.43%), with 4HCl‐RM performing the best. It could be attributed to the high cracking ability of Fe2O3 and Al2O3 on cellulose and hemicellulose. The biomass‐to‐catalyst mass ratio significantly affected the yield of small molecular products, showing a nonlinear trend.

Integrated Prediction of Gas Metal Arc Welding Multi-Layer Welding Heat Cycle, Ferrite Fraction, and Joint Hardness of X80 Pipeline Steel

X80 pipeline steel is widely used in oil and gas pipelines because of its excellent strength, toughness, and corrosion resistance. It is welded via gas metal arc welding (GMAW), risking high cold crack sensitivities. There is a certain relationship between the joint hardness and cold crack sensitivity of welded joints; thus, predicting the joint hardness is necessary. Considering the inefficiency of welding experiments and the complexity of welding parameters, we designed a set of processes from temperature field analysis to microstructure prediction and finally hardness prediction. Firstly, we calculated the thermal cycle curve during welding through multi-layer welding numerical simulation using the finite element method (FEM). Afterwards, BP neural networks were used to predict the cooling rates in the temperature interval that ferrite nuclears and grows. Introducing the cooling rates to the Leblond function, the ferrite fraction of the joint was given. Based on the predicted ferrite fraction, mapping relationships between joint hardness and the joint ferrite fraction were built using BP neural networks. The results shows that the error during phase fraction prediction is less than 8%, and during joint hardness prediction, it is less than 5%.

Research on Flower Pattern and Roll Positioning Optimization for Roll Forming Process of TA4 Coiled Tubing.

Titanium alloy coiled tubing (CT) has great superiority while operating in deep wells with severe conditions, but it faces serious challenges during roll forming like high springback, edge cracking and surface wearing. In order to utilize the high precision and high efficiency production of titanium alloy CT, it is urgently necessary to develop a detailed process design. Based on the W-forming strategy and the cubic curve of the strip edge projection, the flower pattern and roll design for the 21-pass roll forming process were completed. Different tube dimensions and roll positionings were researched regarding the aspects of contact state, stress-strain distribution and geometry ovality using numerical simulation. The thickness/diameter ratio of the tube that can be formed should be within an effective range: exceeding the range leads to edge cracking, and an insufficient ratio leads to high springback. Roll positioning significantly affects the contact state and stress distribution, but leads to no major differences in the tube geometry. Finally, the trial production of the TA4 titanium CT with a size of Φ50.8 × 4 mm was completed successfully and was consistent with the simulation results.

Inhibition of interlaminar damage in CFRP laminates by inserting non-woven carbon fiber interlaminar reinforced tissue

Carbon fiber-reinforced plastics (CFRPs) are known for their high strength and stiffness, essential in high-performance applications. However, in complex structures with fiber discontinuities, such as tapered sections and bolt holes, CFRP laminates are prone to interlaminar damage due to low interlaminar toughness. This study aimed to enhance CFRP interlaminar fracture toughness by inserting non-woven carbon-fiber-reinforced layers. Two non-woven tissues were used: resin-impregnated conventional carbon fiber and resin-free recycled carbon fiber. Evaluations of modes I and II interlaminar fracture toughness revealed that laminates with non-woven inserts had fracture toughness values two to three times higher than pristine CFRP. Non-woven tissues of varying lengths were embedded at ply discontinuities, and tensile tests were conducted to assess their effectiveness. Results confirmed that both non-woven tissues significantly improved interlaminar toughness and effectively suppressed delamination, attributed to high fiber content and complex crack paths, enhancing energy absorption and mechanical performance in CFRP laminates.

2D Polyamides Enable Self-Healing and Recyclable Elastomers with High Robustness, Toughness, and Crack Resistance via Supramolecular Interactions.

High-performance elastomers with exceptional mechanical properties and self-healing capabilities have garnered significant attention due to their wide range of potential applications. However, designing elastomers that strike a balance between self-healing capabilities and mechanical properties remains a considerable challenge. Inspired by biological cartilage, a highly robust, tough, and crack-resistant self-healing elastomer is presented by incorporating hydrogen-bond-rich 2D polyamide (2DPA) into a poly(urethane-urea) matrix. This integration enhances supramolecular interactions driven by multiple hydrogen bonds. The resulting elastomer exhibits impressive strength (54.6 MPa), remarkable elongation at break (705.4%), exceptional toughness (116.7 MJ m-3), outstanding crack resistance (fracture energy up to 187.2 kJ m-2), high self-healing efficiency (98.9% at 50°C for 9 h, 97.9% at room temperature for 48 h), and excellent recyclability, capable of lifting ≈40000 times its own weight. Furthermore, a damage-tolerant, fatigue-resistant anticorrosive coating from this elastomer, showcasing its potential for protective skin applications in underwater robotics is developed. The underlying enhancement mechanism is validated through testing of various elastomers and molecular dynamics simulations, confirming the potential of engineering 2DPA for high-performance elastomers by leveraging supramolecular interactions.

Effect of scanning strategy on the thermo-structural coupling field and cracking behavior during laser powder bed fusion of Ti48Al2Cr2Nb alloys

Laser powder bed fusion (LPBF) is characterized by complicated non-equilibrium processing characteristics, involving extremely high temperature gradient and cooling rate within the mesoscopic dynamic molten pool, which brings great challenges to the forming of metal materials with high crack sensitivity (such as γ-TiAl alloy). In this paper, based on the LPBF forming process of Ti48Al2Cr2Nb alloy, a corresponding multi-track and multi-layer thermal-structure sequential coupled finite element model was constructed, and the influence of four different scanning strategies on the temperature and stress evolution behavior in the powder bed forming region was quantitatively studied, and the crack initiation criterion was also established according to the relationship between nodal flow stress and equivalent stress. It was found that island scanning strategy could induce the higher molten pool temperature and attendant larger molten pool size compared with the non-island linear scanning strategy. Besides, island scanning strategy was conducive to relieving the thermal stress inside the division region but also inducing the stress concentration in the sub-island overlap region. Specially, the strip island scanning strategy exhibited the lowest residual stress and most homogeneous stress distribution. By the experimental measurements, the strip island scanning strategy contributed to the lowest crack density of 0.33mm/mm2.

Crack inhibition of non-weldable Inconel 738 alloy in ultrasound-assisted laser directed energy deposition

High crack susceptibility restricts reliable laser directed energy deposition (L-DED) and repair of γ′ precipitation-strengthened Nickel-based superalloy Inconel 738. This study investigates the effects of ultrasonic assistance synergized with reduced heat input on microstructures and mechanical properties of the L-DED Inconel 738 alloy. The mechanisms of inhibiting crack initiation and propagation of are studied. Results demonstrate that grain refinement and suppression of epitaxial growth of L-DED Inconel 738 alloy are achieved by ultrasonic assistance. The microstructures evolve from coarse columnar grains (∼82.6 μm) to a bimodal structure of shorter columnar and finer equiaxed grains (∼40 μm). The morphologies of MC carbides transform from a continuous distribution of larger sizes to a discrete distribution of finer sizes. Cracks are highly susceptible to propagate along the long, straight grain boundaries of the coarse columnar grains in deposit without ultrasonic assistance, while tortuous grain boundaries induced by ultrasonic assistance enhance crack resistance and inhibit crack propagation. As a result, crack-free L-DED Inconel 738 alloys with excellent ultimate tensile strength of 1478–1490 MPa and elongation of 15.3–17.8 % are achieved via ultrasonic assistance and are significantly higher than cast Inconel 738 (945 MPa, 7.5 %), indicating the feasibility of utilizing ultrasonic assistance to inhibit cracking in L-DED Inconel 738 alloy.

Direct electron detection for EBSD of low symmetry & beam sensitive ceramics

Electron backscatter diffraction (EBSD) is a powerful tool for determining the orientations of near-surface grains in engineering materials. However, many ceramics present challenges for routine EBSD data collection and indexing due to small grain sizes, high crack densities, beam and charge sensitivities, low crystal symmetries, and pseudo-symmetric pattern variants. Micro-cracked monoclinic hafnia, tetragonal hafnon, and hafnia/hafnon composites exhibit all such features, and are used in the present work to show the efficacy of a novel workflow based on a direct detecting EBSD sensor and a state-of-the-art pattern indexing approach. At 5 and 10 keV primary beam energies (where beam-induced damage and surface charge accumulation are minimal), the direct electron detector produces superior diffraction patterns with 10x lower doses compared to a phosphor-coupled indirect detector. Further, pseudo-symmetric variant-related indexing errors from a Hough-based approach (which account for at least 4%-14% of map areas) are easily resolved by dictionary indexing. In short, the workflow unlocks fundamentally new opportunities to characterize materials historically unsuited for EBSD.

Multiple defect-driven high temperature fatigue internal cracking mechanisms of nickel-based superalloy fabricated by laser powder bed fusion at same stress level

Defects generated during additive manufacturing (AM) significantly impact on the fatigue properties of AM materials, but the associated failure mechanisms with some factors including temperature, cycles, and stress are not fully understood. Here, combined with the testing technologies including scanning electron microscopy, three-dimensional ultra-depth of field, and electron backscatter diffraction, the fatigue tests at 650 ℃ with a stress ratio of −1 are performed to investigate the defect-driven failure mechanism for nickel-based superalloy fabricated by laser powder bed fusion (L-PBF). Three different internal failure modes at the same stress level are observed. Results show that the number of crystallography facets increases with the number of load cycles. Fatigue sensitivity levels increase successively in terms of the type, number, size, and location of the defect. The crack growth path is tortuous and exhibits through-crystal fracture. Finally, three internal failure mechanisms of L-PBF nickel-based superalloy are elucidated.

Next Generation Cathode Catalyst Layer Design with High Oxygen Permeable Ionomer – Benefits, Challenges, and Prospects for Heavy Duty Fuel Cell Applications

Proton Exchange Membrane Fuel Cell (PEMFC) has a growing demand to power zero emission fuel cell applications. Ballard is the fuel cell industry leader, developing the next generation core technology to fulfill such demand and giving continuous efforts on cost reduction. Key requirements in fuel cell market applications include high power density and long-life operation, while maintaining high efficiencies and reducing costs. This places a high demand on improving catalyst performance and electrode layer transport, which can be sustained over the duration of the product lifetime. To reduce fuel cell membrane electrode assembly (MEA) cost, the push for high performance catalyst layers (CLs) with low platinum (Pt) loadings results in new challenges for the cathode material selection and electrode design. The increased oxygen transport resistance that occurs at lower catalyst loadings with reduced available catalyst electrochemical active surface area (ECSA), causes two very closely related challenges: 1) greater performance losses at high current density increases the difficulty to achieve the power requirements for the heavy duty market, and 2) the loss of catalyst ECSA via platinum dissolution over time puts additional demands on the design to achieve the end of life (EOL) performance requirement. Therefore, a combination of material solution, design choice and processing parameters are the key to optimize next generation cathode design for fuel cell applications1.One material solution to achieve high performance while reducing catalyst loadings is the development of high oxygen permeable ionomer (HOPI) that mitigates oxygen transport limitations at the Pt surface. Chemours has developed a HOPI with a bulky, sterically rigid monomer group in the ionomer backbone, which disrupts the packing density, improving oxygen permeability on the catalyst surface2. One of the key challenges of HOPI integration and the scale-able fabrication of the catalyst layer is high crack density of CL due to the rigid nature of the ionomer. Ballard has integrated HOPI in the cathode CL overcoming scale-able fabrication challenges through appropriate process parameter selection and evaluated CL performance. The use of accelerated testing and modeling approach developed by numerous product iteration, has been applied for lifetime estimation for HOPI technology introduction. In this talk, we will discuss details about benefit of High Oxygen Permeable Ionomer (HOPI) in next generation cathode CL design.Recently, key requirements in heavy-duty market applications are placing more importance on high efficiency rather than high power density to reduce fuel cost rather catalyst cost. Reaching the target lifetime, catalyst overloading to 0.45 mg/cm2 total Pt in anode and cathode, and 44% active membrane area oversizing are suggested3. Therefore, to achieve high efficiency target, high catalyst activity is more desired. Interestingly, HOPI also showed high specific activity due to the mitigation of catalyst poisoning by sulfonate anion groups4. We will also discuss the catalyst layer design prospect with HOPI for such transition on heavy duty market application.Acknowledgement: US Department of Energy (DOE) funded heavy duty MEA development project (DE-EE0008822).References M. Dutta, A. Young, V. Colbow, J. Bellerive and S. Knights 2020 Examining Catalyst Layer Design Strategies for Improved Fuel Cell Performance and Durability. ECS PRiME 2020S. Litster et al. 2020 Durable High-Power Density Fuel Cell Cathodes for Heavy-Duty Vehicle. DOE AMR 2020K. Ahluwalia and X. Wang 2024 Performance and Durability of Hybrid Fuel Cell Systems for Class-8 Long Haul Trucks. J. Electrochem. Soc. 171 034507R. Jinnouchi, K. Kudo and K. Kodama 2021 The role of oxygen-permeable ionomer for polymer electrolyte fuel cells. Nat Commun 12, 4956.

Effect of Hydrogen on High Cycle Fatigue Properties of L360 Pipeline Steel Notched Specimens.

The fatigue characteristics of notched specimens of L360 pipeline steel in hydrogen and nitrogen environments were investigated by high cycle fatigue life tests and fatigue crack growth rate tests. The fracture morphology in the nitrogen environment was dominated by microcracks and fatigue strips. The fatigue fracture had distinctly different regions in the hydrogen environment. The outer region of the fracture in the hydrogen environment was similar to the nitrogen environment, but a large number of hydrogen embrittlement features were found in the inner region. The fatigue crack growth rate tests were analyzed in conjunction with fatigue life tests. It was found that more fatigue cycles were required to achieve the stress intensity factor ΔK for rapid hydrogen-promoted crack propagation at lower stress. The region with hydrogen embrittlement features increases with decreasing stress.

Structural condition assessment of asphalt pavement semi-Rigid bases using FWD deflection basin parameters

Assessing structural conditions of semi-rigid bases in asphalt pavements is essential for effective base treatment in reconstruction and expansion (R&E) projects. Although various falling weight deflectometer (FWD) parameters have been developed for this purpose, field-validated parameters are still missing. This study identifies the appropriate FWD deflection basin parameter (DBP) through sensitivity analysis, correlation examination, and on-site milling and inspection. Findings indicate D20-D60 as the most suitable DBP, with 23 µm and 40 µm thresholds for warning and severe conditions, respectively. The correlation between D20-D60 and cracking rate suggests that high cracking rates suggest base weakness, whereas low rates may not guarantee structural integrity due to maintenance masking effects. On-site milling further confirmed this finding, demonstrating the alignment between D20-D60 assessments and field observations. The outcome of this study is anticipated to provide a practical DBP for evaluating semi-rigid base conditions and to inform base treatment strategies in R&E projects.

Study on the Characteristics of Steel Slag and its Road Performance in Asphalt Mixture

Based on the characteristics of steel slag, the application progress of steel slag as aggregate in asphalt mixture is summarized. Firstly, the differences in mechanical properties, chemical composition and physical structure of steel slag aggregates treated by different methods are summarized. The surface structure of steel slag is rough and rich in edges and corners, showing good wear resistance and crushing resistance, but there are also problems such as high density, high water absorption and volume instability. Among them, volume instability is the key factor affecting the application of steel slag in asphalt mixture. Then, the effects of steel slag aggregate on the road performance of asphalt mixture, such as water stability, rutting resistance, high temperature stability and low temperature cracking resistance, are summarized in detail. It is found that steel slag instead of coarse aggregate in asphalt mixture can improve the performance of skid resistance, rutting resistance and fatigue resistance. The water damage performance is due to the different sources of steel slag, and the uncertainty of the change results is large. On the whole, steel slag instead of aggregate can improve the road performance to a certain extent, but the volume of steel slag aggregate is unstable, which may bring some variability. In the process of road application, targeted regulation should be carried out to ensure the stability of asphalt mixture performance.

Analysis of initiation and growth of new transverse cracks in high crack density regions in cross-ply laminates

In cross-ply laminates under loading, multiple intralaminar (transverse) cracking in the 90-layers causes laminate stiffness reduction which can be predicted by analytical models studying average of the stress perturbation between transverse cracks. The commonly used analytical models such as shear-lag type or variational-type models assume that stress in damaged 90-layers does not depend on the laminate thickness coordinate. But with increase in crack density, the stress perturbations created by transverse cracks start to interact, generating high stress gradients in through-the-thickness direction in the 90-layers. Location of a new crack and features of its propagation in a high stress gradient region between two cracks in a cross-ply laminate are analyzed in this paper. FEM is used to calculate stress distribution between two cracks. The location of the next crack and its initial orientation is found using principal stresses and orientation of principal axes. Most often these cracks are initiated at ply interface in the middle between already existing cracks. Their propagation across the layer thickness is analyzed using energy release rate based criterion. It is shown that at very high crack density the crack propagation across the layer thickness is unstable in the beginning, but it is stopped when approaching the middle of the layer where the crack opening becomes zero. Presence of local delaminations at the tips of existing cracks changes the energy release rate for propagation of new transverse cracks.

Microscale heat and mass transfer characteristics of CO2 flooding in nanotubes of tight oil reservoirs

AbstractThe mechanism of heat and mass transfer in tight oil reservoirs after CO2 injection is complex. In this paper, first, a CO2 transfer model within microscale adjacent nanotubes in tight oil reservoirs is established. Then, the typical heat and mass transfer characteristics of microscale CO2 in tight oil reservoirs is analyzed, and the influence of grid density on the calculation results is discussed. Finally, the influence of thermal conductivity of tight oil reservoirs on CO2 physical properties parameters is revealed. Results show that: (a) From the inlet end of the thick nanotube to the outlet of the nanotube, the pressure of CO2 drops from 3.5 to 3.3697 MPa. (b) When the mesh length is equal to 5 nm, the CO2 pressure in the thin nanotube drops from 3.5 to 3.3329 MPa, and the CO2 pressure in the thick nanotube drops from 3.5 to 3.2018 MPa. (c) Organic amines react with CO2 to form salts, which can seal high permeability layers and cracks, but there is a risk of environmental pollution.

The regulation of dislocation and precipitated phase improving hydrogen embrittlement resistance of pipeline steel in high pressure hydrogen environment

In this study, the hydrogen embrittlement behavior of quenched pipeline steel tempered at 550 °C to 650 °C in a high-pressure hydrogen environment was analyzed. Hydrogen permeation tests and microstructural analyses indicated that the dislocation density of the steel decreases with increasing tempering temperature, while precipitates gradually nucleate and grow. These hydrogen traps interact with hydrogen atoms, resulting in significantly higher diffusible hydrogen content in steel tempered at 550 °C compared to that tempered at 600 °C and 650 °C. Fatigue crack growth (FCG) test results show that steel tempered at 600 °C and 650 °C exhibits significantly better hydrogen embrittlement resistance than steel tempered at 550 °C. This is primarily due to the combined effect of the high hydrogen concentration, high dislocation density and low nano carbide content in the steel tempered at 550 °C, which inhibits dislocation slip and emission, leading to high crack tip stress and rapid crack propagation. In contrast, the low dislocation density and and dispersed nano carbides in steel tempered at 600 °C and 650 °C facilitate some dislocation slip and emission, result in crack tip stress relaxation and reduced crack propagation rate. Properly controlling the initial dislocation density and increasing the density of irreversible hydrogen traps can enhance the strength of materials while improving their resistance to hydrogen embrittlement.

A machine vision‐based intelligent segmentation method for dam underwater cracks using swarm optimization algorithm and deep learning

AbstractEnsuring the safety of water networks is a research hotspot in the current water conservancy industry, and dams are an important part. However, over time, the dam is prone to varying degrees of aging and disease, most of which are structural cracks. If they cannot be discovered and repaired in time, the normal operation of the dam will be affected, and even catastrophic accidents such as dam failure will occur. However, complex backgrounds and blurred images can easily lead to misjudgments by machine vision detection models, and high‐efficiency and accurate detection and evaluation technology are urgently needed. This paper combines the deep semantic segmentation network and the model hyperparameters optimization algorithm to propose a data‐intelligent perception method of dam underwater cracks driven by knowledge coupling. Taking the underwater detection of a concrete face rockfill dam as an example, the effectiveness of the model is verified by using the underwater vehicle as the carrier. Experimental results indicate that the developed method achieves an intersection‐union ratio of 0.9301, a precision rate of 0.9678, a precision rate of 0.9472, and a recall rate of 0.9577 in the test set. This shows that the constructed method has a high crack fine detection performance. In addition, the developed method has better segmentation performance in different complex underwater crack scenes, which further illustrates the high performance of the developed method.

Tailored porosity in additive manufacturing of 7075 aluminum alloy for crack suppression and high strength

Laser-directed energy deposition (LDED) additive manufacturing of 7075 aluminum (Al) alloy is highly challenging due to the inherent poor printability and high cracking tendency. Here, we disclose a new approach to suppress cracking in LDED-processed 7075 Al alloy by engineered porosity (about 1.14 %). The crack-free 7075 Al alloy was achieved by slightly sacrificing the densification. Further increasing the density of the material by increasing laser energy input leads to cracking. The mechanisms of minor pores in alleviating cracks are mainly reflected in three aspects: (i) pores disrupt the epitaxial growth of columnar grains; (ii) free-form surfaces surrounding pores could release the accumulated residual stress, and (iii) more dislocations near pore drive nucleation of near equiaxed grains. The LDED-processed crack-free 7075 Al alloy after heat treatment shows an ultimate tensile strength of 464 ± 12 MPa and break elongation of 9.7 ± 1.2 %, attaining a good strength-ductility synergy among many additively manufactured 7075 Al alloys in the current literature. Unlike the mainstream additive manufacturing of metallic materials, which pursues high densification to attain high-performance components, this work demonstrates the positive roles of pores in the additive manufacturing of cracking-sensitive materials. The findings of this work highlight new insights regarding the balance between pores and cracks for better manufacturability and higher mechanical performance of materials.