Search Results (17)

Aluminum matrix composites provide an ideal solution for lightweight brake disks, but conventional casting processes are prone to crack initiation due to inhomogeneous reinforcement dispersion, gas porosity, and inadequate toughness. To break the conventional trade-off between high wear resistance and low toughness of brake disks, this study fabricated a bimetallic structure of SiC_p/Al–Fe–V–Si aluminum matrix composite and cast ZL101 alloy using friction stir lap welding (FSLW). Then, the microstructural evolution, mechanical properties, and tribological behavior of the FSLW joints were studied by XRD, SEM, TEM, tensile testing, and tribological tests. The results showed that the FSLW process homogenized the distribution of SiC particle reinforcements in the SiC_p/Al–Fe–V–Si composites. The Al₁₂(Fe,V)₃Si heat-resistant phase was not decomposed or coarsened, and the mechanical properties were maintained. The FSLW process refined the grains of the ZL101 aluminum alloy through recrystallization and fragmented eutectic silicon, improving elongation to 22%. A metallurgical bond formed at the joint interface. Tensile fracture occurred within the ZL101 matrix, demonstrating that the interfacial bond strength exceeded the alloy’s load-bearing capacity. In addition, the composites exhibited significantly enhanced wear resistance after FSLW, with their wear rate reduced by approximately 40% compared to the as-received materials, which was attributed to the homogenized SiC particle distribution and the activation of an oxidative wear mechanism. Full article

This study investigates the structural integrity and dynamic behavior of symmetry-optimized battery pack systems for new energy vehicles through advanced finite element analysis. It examines symmetry-optimized battery pack systems with mechanically stable and thermally adaptive potentials. Leveraging geometric symmetry principles, a high-fidelity three-dimensional (3D) model was constructed in SolidWorks 2023 and subjected to symmetry-constrained static analysis on ANSYS Workbench 2021 R1 platform. The structural performance was systematically evaluated under three critical asymmetric loading scenarios: emergency left/right turns and braking conditions, with particular attention to symmetric stress distribution patterns. The numerical results confirmed the initial design’s compliance with mechanical requirements while revealing symmetric deformation characteristics in dominant mode shapes. Building upon symmetry-enhanced topology configuration, a novel lightweight strategy was implemented by substituting Q235 steel with ZL104 aluminum alloy. While mechanical symmetry has been widely studied, thermal gradients in battery packs can induce asymmetric expansions. For example, uneven cooling may cause localized warping in aluminum alloy shells. This multiphysics effect must be integrated into symmetry constraints to ensure true stability. Symmetric material distribution optimization reduced the mass by 19% while maintaining structural stability, as validated through comparative static and modal analyses. Notably, the symmetric eigenfrequency arrangement in optimized modules effectively avoids common vehicle excitation bands (8–12 Hz/25–35 Hz), demonstrating significant resonance risk reduction through frequency redistribution. This research establishes a symmetry-driven design paradigm that systematically coordinates structural efficiency with dynamic reliability, providing critical insights for developing next-generation battery systems with balanced performance characteristics. Full article

With the global shift in energy structure and the advancement of the “double carbon” strategy, methanol has gained attention as a clean low-carbon fuel in the engine sector. However, the corrosion–wear coupling failure caused by acidic byproducts, such as methanoic acid and formaldehyde, generated during combustion severely limits the durability of methanol engines. In this study, we employed a systematic approach combining the construction of a corrosion liquid concentration gradient experiment with a full-load and full-speed bench test to elucidate the synergistic corrosion–wear mechanism of core friction pairs (cylinder liner, piston, and piston ring) in methanol-fueled engines. The experiment employed corrosion-resistant gray cast iron (CRGCI), high chromium cast iron (HCCI), and nodular cast iron (NCI) cylinder liners, along with F38MnVS steel and ZL109 aluminum alloy pistons. Piston rings with DLC, PVD, and CKS coatings were also tested. Corrosion kinetic analysis was conducted in a formaldehyde/methanoic acid gradient corrosion solution, with a concentration range of 0.5–2.5% for formaldehyde and 0.01–0.10% for methanoic acid, simulating the combustion products of methanol. The results showed that the corrosion depth of CRGCI was the lowest in low-concentration corrosion solutions, measuring 0.042 and 0.055 μm. The presence of microalloyed Cr/Sn/Cu within its pearlite matrix, along with the directional distribution of flake graphite, effectively inhibited the micro-cell effect. In high-concentration corrosion solutions (#3), HCCI reduced the corrosion depth by 60.7%, resulting in a measurement of 0.232 μm, attributed to the dynamic reconstruction of the Cr₂O₃-Fe₂O₃ composite passive film. Conversely, galvanic action between spherical graphite and the surrounding matrix caused significant corrosion in NCI, with a depth reaching 1.241 μm. The DLC piston coating obstructed the permeation pathway of formate ions due to its amorphous carbon structure. In corrosion solution #3, the recorded weight loss was 0.982 mg, which accounted for only 11.7% of the weight loss observed with the CKS piston coating. Following a 1500 h bench test, the combination of the HCCI cylinder liner and DLC-coated piston ring significantly reduced the wear depth. The average wear amounts at the top and bottom dead centers were 5.537 and 1.337 μm, respectively, representing a reduction of 67.7% compared with CRGCI, where the wear amounts were 17.152 and 4.244 μm. This research confirmed that the HCCI ferrite–Cr carbide matrix eliminated electrochemical heterogeneity, while the DLC piston coating inhibited abrasive wear. Together, these components reduced the wear amount at the top dead center on the push side by 80.1%. Furthermore, mismatches between the thermal expansion coefficients of the F38MnVS steel piston (12–14 × 10⁻⁶/°C) and gray cast iron (11 × 10⁻⁶/°C) resulted in a tolerance exceeding 0.105 mm in the cylinder fitting gap after 3500 h of testing. Notably, the combination of a HCCI matrix and DLC coating successfully maintained the gap within the required range of 50–95 μm. Full article

The hybrid laser inertial navigation system (INS) is increasingly vital for high precision under high-dynamic, long-duration conditions, especially in complex aircraft environments. Key components like the base, platform, and inner/outer frames significantly impact system accuracy and stability through thseir static and dynamic characteristics. This study focuses on minimizing deviations in the INS body coordinate system caused by elastic deformation under high overload by developing a mechanical simulation model of a rotational modulation structure and a structural model of the outer frame assembly. A reliability analysis model is established, considering both functional and structural strength failures. To address uncertainties from manufacturing, technical conditions, material selection, and assembly errors, a global sensitivity analysis based on Bayesian inference evaluates parameter contributions to functional failure probability, using a sample size of N1 = 5 × 10⁵. Additionally, uncertainty analysis via Sobol sequence sampling (N2 = 10,000) examines the impact of mean design parameter variations on failure probability for ZL107 and SiCp/Al aluminum matrix composite frames. Experimental verification concludes the study. The results indicate that the SiCp/Al composite material demonstrates superior mechanical performance compared to traditional materials such as the ZL107 aluminum alloy. The uncertainties in the inner frame thickness, inner frame material strength, and outer frame thickness have the most significant impact on the probability of functional failure in the hybrid INS, with sensitivity indices of ${\delta }_6^{P\left\{F\right\}}$ = 0.01657, ${\delta }_2^{P\left\{F\right\}}$ = 0.00873, and ${\delta }_4^{P\left\{F\right\}}$ = 0.00818, respectively. The mechanical properties of the outer frame structure made from SiCp/Al are significantly enhanced, with failure probabilities across three failure modes markedly lower than those of the ZL107 frame, indicating high reliability. In an impact test conducted on the product, the laser gyroscope worked normally, the hybrid laser system function was normal, and the platform angular velocity change corresponding to each impact direction was less than 12 ″/s. The maximum angle change of the inner and outer frames was 0.107°, indicating that the system structure can withstand large overloads and multiple levels of mechanical environments and has good environmental adaptability and reliability. This analytical approach provides a valuable method for reliability evaluation and design of new hybrid INS structures. More importantly, it provides insights into the influence of design parameter uncertainties on navigation accuracy, offering critical support for the advancement of inertial technology. Full article

The effects of red mud on the microstructures and high-temperature tensile properties of the ZL109 aluminum alloy have been investigated. Red mud/ZL109-based composite materials with added red mud (a major byproduct of the aluminum industry), which has been coated with nickel by chemical deposition, have been prepared through gravity casting. The results show that the addition of red mud promotes the alloy’s microstructure and helps to uniformly distribute the eutectic silicon. It also increases the content of heat-resistant phases, such as the Q-Al₅Cu₂Mg₈Si₆ and γ-Al₇Cu₄Ni phases. These changes significantly enhance the alloy’s high-temperature tensile properties. The alloy with 1% (wt.%) red mud exhibits the best tensile strength at both room temperature and 350 °C, reaching 295.4 MPa and 143.3 MPa, respectively. The alloy with 1.5% (wt.%) red mud demonstrates excellent performance at 400 °C, achieving a tensile strength of 86.2 MPa through the cut-through method and Orowan mechanism. As a reinforcing material, red mud not only improves the high-temperature resistance of the aluminum alloy but also provides a way to recycle industrial waste. This study offers a new way to address the red mud waste problem and helps develop high-performance, heat-resistant aluminum alloys. It shows the potential of these alloys in high-temperature applications. Full article

As the core component of chain-less ammunition transmission system, the large long lead cylinder adopts ZL205A alloy, which has the advantages of high strength and wear resistance. However, in its main casting production process, the forming quality is mainly determined by the casting process parameters under the premise of determining a reasonable casting system. Considering that the casting process parameters are the process feedback expression of the macroscopic forming quality and comprehensive mechanical properties by controlling the coupling effect of the metal liquid flow in the microscopic flow field, the directional solidification crystallization of the alloy and the solid–liquid heat transfer and heat transfer during the filling and solidification process, the accurate and reasonable selection of casting process parameters is conducive to the stable guarantee of pouring quality. On the basis of the optimized column gap casting system, this study combined numerical simulation and data statistics. Within the rationality of each casting process parameter constructed by single-factor analysis, the response surface method was used to construct a quantitative guidance relationship of each process parameter coupling mapping casting defect, and based on this model, the optimal process parameter combination was realized as follows: compared with traditional metal mold casting and unoptimized low pressure casting, the tensile strength of non-porous casting with holding pressure 14.68 kPa, casting temperature 717.152 °C and mold preheating temperature 256.12 °C increased by 6.6% and 4.1%, respectively, hardness increased by 14.3% and 8.4% respectively, and the elongation is increased by 16.9% and 10.6%, respectively, thus efficiently and accurately improving the process quality. Full article

The effects of rare earth Y on the microstructures and tensile properties of ZL109 alloys were studied through metallographic observation, scanning electron microanalysis, X-ray diffraction, and tensile experiments, and the existence form and mechanism of Y were analyzed. The results show that the grain size of the ZL109 alloy is obviously reduced and that the strength of the ZL109 alloy is significantly increased after adding the Y element. When the Y content is increased to 0.2 wt.%, the tensile properties of the ZL109 alloy at room temperature and 350 °C are better than those without a rare earth addition, and the comprehensive tensile properties are better. This is due to the addition of the Y element; α-Al dendrites are obviously refined, and there is a tendency for them to change into fine isometric crystals. The size of the eutectic Si decreases, and its shape is modified. The morphology and size of high temperature enhanced phases, such as Al₃CuNi, are optimized. The heat-resistant enhanced phase Al₂Si₂Y is formed after the addition of rare earth Y. However, with the addition of the Y element, the Al₂Si₂Y phase increases, and coarsening results in the decrease in alloy strength. Full article

The arc torch angle greatly affected the deposition characteristics in the wire arc additive manufacturing (WAAM) process, and the relation between the droplet transition behavior and macrostructure morphology was unclear. This work researched the effect of torch angle on the formation accuracy, droplet transition behavior and the mechanical properties in the WAAM process on a ZL205A aluminum alloy. The results suggested that at the obtuse torch angle, part of the energy input was used to heat the existing molten pool, which was optimized for the longer solidification period of the molten pool. Therefore, the greater layer penetration depth at 100° resulted in the improved layer-by-layer combination ability. The obtuse torch angle was associated with the better formation accuracy on the sidewall surface due to the smaller impact on the molten pool, which was influenced by both the arc pressure and droplet impact force. The eliminated pores were optimized for the mechanical properties of depositions at a torch angle of 100°; thus, the tensile strength and elongation attained maximum values of 258.6 MPa and 17.1%, respectively. These aspects made WAAM an attractive mode for manufacturing large structural components on ZL205A aluminum alloy. Full article

The ZL205A aluminum alloy is mostly used in automobiles, aircraft, aerospace, and other mechanical components, but now, it focuses on the study of its casting performance, and there is still a lack of research on its cutting performance. In this paper, the milling ZL205A aluminum alloy was milled for testing and simulation analysis. The milling test showed that the impact of the axial cutting depth, radial cutting depth, feed, and cutting speed on the milling force was successively reduced. A thermodynamic analysis model is proposed to evaluate the cutting force and tool design in milling. The model considers the front angle and friction angle of the tool, in which the friction angle is adjusted by the friction coefficient, the variable is the cutting parameter, the constant is fitted through the milling experiment, and the effectiveness of the model is verified to predict the milling force. The pre-grinding test was carried out before the experiment, and the stability of the test was proved by observing the macroscopic shape of the chip and the wear of the cutting edge. The model comprehensively considers the tool angle and quickly calculates the minimum load on the milling cutter based on the optimal geometric parameters, which can be used to optimize the milling cutter structure and provide a theoretical basis for the preparation of ZL205A aluminum alloy mechanical components. Full article

In this paper, the abnormal fracture failure of a ZL104 aluminum alloy quick-opening manhole cover of a cement tank truck is systematically studied to discover the root cause of an accident. The unloading operation procedures of cement tank trucks, the effectiveness of safety valves, the chemical composition, mechanical properties and material quality of aluminum alloy manhole covers, and the macroscopic and microscopic morphology of fractures were comprehensively analyzed. The results show that although the Mg content in the chemical composition of an aluminum alloy manhole cover exceeds the standard, it is not the root cause of the accident. The root cause of the failure is that, during the unloading operation, the operator did not strictly follow the unloading procedures. One of the buckles was in the released state, which led to uplift cracking, resulting in the successive cracking and slipping of adjacent buckles, and the manhole cover finally cracked and flew out. Based on the failure causes, suggestions are put forward to prevent the manhole cover from failing during the unloading operation of cement tank trucks in the future. Full article

In this paper, ZL205A (AlCu5Mn alloy) castings were prepared by squeeze casting. The effects of solution and ageing treatment on the microstructure and mechanical properties of ZL205A castings were studied by metallography, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and mechanical properties tests. The results showed that most of the θ(Al₂Cu) and T(Al₁₂CuMn₂) phases in squeeze-cast ZL205A dissolved into the α(Al) matrix after solution treatment for 15 h. The fine precipitates gradually increased with the ageing time. The ultimate tensile strength of the specimen aged for 6 h was the highest of 467 MPa and the elongation was up to 15.1%, showing good comprehensive mechanical properties. Full article

The effects of Al–5Ti–0.8C and the rare-earth element La on the microstructure and high-temperature mechanical properties of ZL205A alloy were investigated. We found that the grains of 0.1%La + 0.3%Al–5Ti–0.8C alloy were fine, the morphology of the as-cast Al₂Cu phase was fragmented, and the precipitated phase was fine after T5 treatment. In particular, the high-temperature mechanical properties of 0.1%La + 0.3%Al–5Ti–0.8C alloy were significantly improved above 250 °C. The reason for the increase in high-temperature plasticity was attributed to the Al–La phase and the TiC particles, which refined the grains and reduced the tendency for intergranular fracture at high temperatures. More importantly, the high-temperature strengthening mechanism of the Al–5Ti–0.8C master alloy compounded with La was a result of the TiC introduced by the Al–5Ti–0.8C alloy, and the Al₁₁La₃ formed by the addition of La refined the grains in the matrix, promoted the precipitation of the needle-like θ’(Al₂Cu) phase, reduced the size of the θ’(Al₂Cu) phase, decreased the PFZ (Precipitation Free Zone), and increased the θ’(Al₂Cu) phase number, hindering dislocation and grain boundary motion. Full article

In this study, a new type of Al-TiO₂-C-Er₂O₃ refiner was prepared by exothermic dispersion, and the refiner was added to a ZL205 alloy to investigate the effect of the Al-TiO₂-C-Er₂O₃ refiner on the refinement effect and corrosion resistance of the ZL205 alloy. The results reveal that, with the increase in the Er₂O₃ content, the refining effect is first enhanced and then reduced. The best refining effect of the Al-TiO₂-C-Er₂O₃ refiner was observed by the addition of 6% Er₂O₃, which refined the grain size of the ZL205 alloy from 147 μm to 103.9 μm, and the grain size was 72% of the ZL205 alloy. The addition of the Al-TiO₂-C-Er₂O₃ refiner led to the improved bias agglomeration of the CuAl₂ phase at the grain boundaries in ZL205 and reduced the corrosion sensitivity of the alloy; moreover, the α-Al nucleation temperature of the ZL205 alloy increased, the crystallization interval ΔT of the CuAl₂ phase increased from 7.4 °C to 9.3 °C, corresponding to an increase of 1.9 °C, and the self-corrosion current density (i_corr) of the ZL205 alloy was reduced from (2.83 × 10⁻⁵ A/cm²) to (6.26 × 10⁻⁶ A/cm²), a decrease of 77.8%; the polarization resistance (R₁ + R₂) was 1808.62 Ω·cm² in comparison with that of the original ZL205 alloy (480.42 Ω·cm²), corresponding to a 276.7% increase. Full article

The effects of Al–Ti–C and La on the fluidity of a ZL205A alloy after separate and combined addition were studied by conducting a fluidity test. The fluidity of the ZL205A alloy first increased and then decreased with the increasing addition of Al–Ti–C and La; it peaked at 0.3% and 0.1% for Al–Ti–C and La, respectively. The combined addition of Al–Ti–C and La led to better fluidity, which increased by 74% compared with the base alloy. The affecting mechanism was clarified through microstructure characterization and a DSC test. The heterogeneous nucleation aided by Al–Ti–C and La, the number of particles in the melt, and the evolution of the solidification range all played a role. Based on the evolution of the fluidity and grain size, the optimal levels of Al–Ti–C and La leading to both high fluidity and small grain size were identified. Full article

In this paper, in order to improve the performance of the ZL205A castings, continuous ultrasonic and pulsed ultrasonic treatments were applied to the melted alloy to study the effect of ultrasound propagation distance on microstructure and microhardness. The results indicated that ZL205A grains were significantly refined by ultrasonic vibration, but the refinement effect became weak gradually with the increase of sampling depth. The minimum grain sizes were 103.2 μm and 122.5 μm respectively in continuous and pulsed ultrasonic treatment. Grain boundary segregation also became more serious and coarser with the increase of vertical depth. In addition, microhardness and vertical depth are not positively correlated linearly. As the vertical depth increased, microhardness first decreased and then increased, the maximum hardnesses were 73.9 HV and 72.84 HV, respectively, in the two process modes. According to the experiment results and available studies, the mechanism of ultrasonic treatment maybe that: the cooling rate of solidification interface front increased by cavitation and streaming, thus changing the solute redistribution behavior of the ZL205A melt. Full article