最新刊期
卷 47 ， 期 2 ， 2026
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- 摘要：The deep understanding of the martensitic microstructure in directionally solidified Ni-Mn-Ga alloys is crucial for optimizing the magnetic field-induced strain obtained through magnetic field-induced martensite variant reorientation. Although previous studies have systematically characterized the typical micro-configurations and orientation relationships of the strongly textured seven-layer modulated （7M） martensite， the underlying formation basis of these microstructural features remains insufficiently understood. In this work， the characteristics of microstructural morphology and orientation correlation of the 7M martensite in directionally solidified Ni₅₀Mn₃₀Ga₂₀ alloy were systematically characterized using scanning electron microscopy （SEM） and electron backscatter diffraction （EBSD）. On this basis， the formation basis of the typical microstructure was analyzed based on the transformation orientation relationship between austenite and martensite phases. Furthermore， the twinning relations between martensitic variants were theoretically predicted and classified using the phenomenological theory of martensite crystallography （PTMC）. The fundamental reason for the existence of six variant groups and a total of 24 variants within a single austenite grain lies in the multiple transformation paths corresponding to the six sets of ｛101｝A habit planes of the cubic austenite under the transformation routes of Pitsch orientation relationship. The spatial arrangement of lamellar interfaces within different variant groups can manifest as horizontal， vertical， or inclined types， which originates from the geometric position difference of the ｛101｝A orientation relationship planes relative to the directional solidification direction when viewed along the <001>A direction. Further PTMC analysis indicates that 14 types of twinning relations are theoretically possible between 7M martensite variants. The experimentally observed Type I， Type II， and compound twins can all be categorized as conventional twin types. The analysis method used in this work， based on the martensitic transformation orientation relationship， shows good applicability in explaining the martensitic microstructural morphology and variant distribution in Ni-Mn-based alloys. However， the phenomenological theory of martensite transformation is primarily used to predict all theoretically possible twin types between martensite variants and cannot directly determine the specific twinning relations observed in experiments.关键词：martensitic transformation;preferred orientation;martensitic microstructure;twinning relation325|12|0更新时间：2026-05-19
- 摘要：To address the issue that the pitting corrosion resistance of commercial 430 stainless steel varies significantly without systematic clarification on the root cause， cold‑rolled 430 stainless steel sheets from four different steel mills （A，B，C，D） were selected in this study. Their pitting corrosion resistance was systematically compared using immersion tests， critical pitting temperature （CPT） measurements， and pitting potential tests， combined with chemical composition and microstructural characterization. This investigation not only evaluated the theoretical predictability of the pitting resistance equivalent number （PREN）， but also emphasized the decisive role of the actual microstructure on corrosion performance. Results show that A‑430SS exhibits the best pitting corrosion resistance， with the highest average pitting potential （40.7 mV） in 3.5% NaCl solution and the highest CPT （57.3 ℃） in Cl⁻ solution of mass fraction 50×10⁻6， followed by B‑430SS， while C‑430SS and D‑430SS show the poorest performance. Although B‑430SS possesses the highest PREN value （17.61） due to its relatively high mass fraction of Cr （16.78%） and N （0.052%）， its actual corrosion resistance is not optimal. Microstructural analysis reveals that A‑430SS has excellent cleanliness with only 5 type‑D inclusions， much lower than 23 in C‑430SS and 20 in D‑430SS， and a fully recrystallized， uniform and band‑free microstructure， which effectively inhibits pitting nucleation. In contrast， the large number of inclusions and banded structure caused by incomplete recrystallization in B‑430SS greatly weakens its compositional advantage of high PREN. This study clarifies that microstructural defects can dominate the pitting corrosion resistance of commercial 430 stainless steel， invalidating the composition‑based PREN prediction， and provides an important basis for the processing optimization and material selection of high‑performance ferritic stainless steels.关键词：430 stainless steel;pitting;microstructure;critical pitting temperature;pitting resistance equivalent number;pitting potential243|5|0更新时间：2026-05-19
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Effect of Tempering Process on the Mechanical Properties and Wear Resistance of Cr⁃Ni⁃Mo Cast Steel AI导读
摘要：This study systematically investigated the influence of tempering processes on the wear resistance of Cr-Ni-Mo cast steel. Heat treatment schedules were designed using JMatPro software with a quenching temperature of 930 ℃ and tempering temperatures of 520 ℃， 550 ℃， and 580 ℃. The microstructure of the test steel specimens was analyzed by scanning electron microscopy （SEM）， and scratch tests were conducted. Hardness was measured using a Vickers hardness tester， while room-temperature wear resistance was evaluated using a friction and wear testing machine. The results show that with increasing tempering temperature， hardness and strength first increase and then decrease， reaching peak values of 37.5 HRC， 1 207 MPa， and 1 054 MPa at 550 ℃. Elongation exhibits an initial decrease followed by an increase， with a maximum of 13.7% observed at 580 ℃. Overall variations in mechanical properties are relatively minor. Wear volume decreases progressively with rising tempering temperature， achieving the lowest value and thus the best wear resistance at 580 ℃. The friction coefficient curve follows the typical pattern of dry sliding friction wear： a rapid initial rise， followed by a partial decrease， and eventual stabilization. The overall performance is found to be optimal at a tempering temperature of 580 ℃. The heat treatment solutions designed by JMatPro software provide a theoretical basis and process guidance for experimental implementation， enabling the attainment of optimal tempering processes.关键词：JMatPro;heat treatment;carbide;hardness;wear resistance230|4|0更新时间：2026-05-19 - 摘要：Magnesium matrix composites with different graphene nanoplatelet （GNPs） contents were fabricated based on thixomolding technology， and the effects of GNPs content on the microstructure， interfacial structure， and mechanical properties of the composites were systematically investigated. Using AZ91D magnesium alloy as the matrix， composites with GNPs mass fraction of 0.3%， 0.6%， and 0.9% were prepared. The grain morphology was observed by optical microscopy， the dispersion state and failure mode of GNPs were characterized by scanning electron microscopy， and the interfacial structure between GNPs and the matrix was analyzed by transmission electron microscopy. The results show that an appropriate amount of GNPs significantly refines the grains. When the GNPs mass fraction increased from 0.3% to 0.6%， the average grain size decreased from 5.5 μm to 3.5 μm. However， when the GNPs mass fraction further increased from 0.6% to 0.9%， the average grain size increased from 3.5 μm to 4.2 μm. In the composite with 0.6% GNPs， the GNPs were uniformly distributed as thin flakes at both grain boundaries and within the grains， and TEM analysis revealed good interfacial bonding with the magnesium matrix. The failure modes of GNPs during fracture were classified into debonding and fracture. During the thixomolding process， the screw shear effectively achieved uniform dispersion of GNPs and prevented agglomeration； meanwhile， the uniformly dispersed GNPs significantly enhanced the mechanical properties of the composite， increasing the ultimate tensile strength by 21.7%. This study reveals the dispersion behavior and interfacial bonding characteristics of GNPs in magnesium matrix composites， providing an experimental basis for the design and fabrication of high-performance magnesium matrix composites.关键词：semi-solid injection molding;magnesium matrix composites;interface structure;graphene nanoplatelet211|1|0更新时间：2026-05-19
- 摘要：In order to expand engineering application ranges of TC4 titanium alloy with α+β dual-phase， its microstructure and mechanical properties need to be precisely controlled. Taking forged TC4 as the research object， this study aims to optimize its strength-plasticity synergy. Systematically investigated were the effects of three cooling methods （water cooling， air cooling， and furnace cooling） following solution treatment at 920 ℃（40 min）， as well as aging treatments at 500 ℃， 550 ℃， and 600 ℃ for 3 h after water-cooled solution treatment， on the alloy’s microstructure and mechanical properties. Microstructural evolution was observed using optical microscopy （OM） and scanning electron microscopy （SEM）， while mechanical properties were characterized via room-temperature tensile tests. The results indicate that solution cooling significantly influences the alloy’s microstructure. Air cooling induces a stable bimodal microstructure composed of equiaxed primary α grains and lamellar α phases， endowing the alloy with optimal comprehensive mechanical properties. After water-cooled solution treatment， secondary α phases and lamellar α grains gradually coarsen with increasing aging temperature， accompanied by an expansion of the interlamellar spacing. Among these， 550 ℃ is identified as the optimal aging temperature. The alloy achieves the best strength-plasticity balance after combined treatment at 920 ℃ （40 min） water cooling followed by 550 ℃（3 h） aging， with an ultimate tensile strength of 1022 MPa and an elongation of 13%. This study clarifies the optimal solution and aging parameters for forged TC4， and provides reliable technical references and guidance for microstructure-property regulation and heat treatment process formulation in practical engineering.关键词：TC4 titanium alloy;solution treatment;aging treatment;microstructure;mechanical properties229|7|0更新时间：2026-05-19
- 摘要：As an important microstructure organization in materials， the interface has a crucial effect on the properties of alloys. In order to analyse the strengthening mechanism of the interface precipitated phase， it is of great significance to understand the stability of the interface composed with the alloy matrix and its precipitated phase on a micro level. In order to improve the stability of Mg-Sn alloy， based on the first-principles calculation， 4d transition group elements were doped into the Mg2Sn（022）/Mg（0001） interface model constructed by the magnesium matrix and its precipitates Mg2Sn to investigate the beneficial elements that could improve the bonding strength of the interface. The influence mechanism of doping 4d transition elements on the interface stability was analyzed based on the electron transfer and the bond length between the atoms of the interface， and the charge distribution of atoms. The results show that the adhesion energy of the interface is increased with 4d transition group elements doped. The stability of the Mg2Sn（022）/Mg（0001） interface is improved， and the interface with Ru elements doped possesses the highest stability. In addition， it is found that the larger the interface adhesion energy， the smaller the bond length and the more charge transferred between the atoms of the interface. Based on the differential charge density， it is also found that the charge distribution is directional around the Ru atoms at the interface doped. Some of the charge of Mg atoms is transferred to Ru atoms， and some are transferred to Sn atoms at the interface， and the shared charges are found at the interface， which enhances the interaction between atoms.关键词：first-principle;transition group elements;interface;electronic structure156|1|0更新时间：2026-05-19
- 摘要：In the explosion damage environment， the stored shock wave test device has the advantage of high reliability， which has been widely used in ground tests in recent years. Due to the difficulties in underwater testing， there are no special stored shock wave test device for underwater shock waves at present. Based on the stored test principle， a test system suitable for underwater shock wave measurement with high-speed sampling and large-capacity memory was researched. A FPGA was used as the main controller， and a high-speed AD converter with a large-capacity FLASH memory was selected. The focus of the paper was to solve the problem of fast data storage caused by raising the sampling frequency to 10 MHz in current stored shock wave test device， and to meet the index requirements of underwater testing. Functions such as work parameter programming， work status monitoring， and timing start were added to improve the underwater suitability. The test results show that， the stored shock wave test system can completely record the entire process of shock wave overpressure changes caused by underwater explosion， and which can meet the requirements of underwater overpressure testing.关键词：underwater shock wave test;high-speed sampling;large-capacity memory;FPGA;stored test;FLASH13|0|0更新时间：2026-05-19
- 摘要：To address the requirement for rapid verification of a test system’s dynamic response capability in explosive scenarios， a method for evaluating the dynamic characteristics of test systems based on metal wire electro-explosive testing was proposed. An electro-explosive shock wave was employed as the excitation source， and pressure signals were synchronously collected from both the standard system and the system under test. Four key characteristic parameters， i.e.， overpressure peak， rise time， duration and impulse， were extracted for comparative analysis. Based on this methodology， a portable electro-explosive shock wave test system was developed. Repeatability tests of the electro-explosive shock wave demonstrate that the peak overpressure values are consistently around 20 kPa and the duration values around 1.2 ms across six trials， with a repeatability error less than 5%， which satisfies the requirements of field dynamic testing. Comparative tests reveal that the system under test exhibits an approximately 10% peak attenuation， indicating potential limitations in front-end signal conditioning or sensor sensitivity. The rise time of the system under test shows a delay of approximately 10.6%， which suggests insufficient dynamic response speed and bandwidth. The duration and impulse remain within the 10% error margin， demonstrating good consistency with the standard system. This methodology provides an effective supplementary approach for the rapid assessment and usability verification of the dynamic characteristics of test systems in explosive environments， expanding the applicability of dynamic evaluation techniques. However， due to the shaping effect during pipeline propagation， the emphasis on relative performance evaluation， and the limitation in excitation energy scale， it is more suitable for rapid dynamic performance screening in the field rather than replacing high-precision laboratory calibration methods.关键词：electro-explosive shock wave;dynamic characteristic evaluation;field testing;shockwave test system;synchronous acquisition22|1|0更新时间：2026-05-19
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Integrated Protection Method for Electronic Packaging in High Overload and Strong Magnetic Fields AI导读
摘要：To address the vulnerability of onboard electronic packaging equipment to damage and failure under the high overload and strong magnetic shock environment of electromagnetic railguns， this study analyzed the propagation patterns of high overload and strong magnetic shocks. It proposed an integrated protection method for electronic packaging equipment tailored to high overload and strong magnetic environments. Using wave propagation theory， we derived the stress wave and electromagnetic shielding mechanisms within multilayer heterogeneous media， and constructed a constrained model linking stress wave and electromagnetic wave shielding effectiveness to material thickness. The NSGA-II （Non-Dominated Sorting Genetic Algorithm II） was employed to obtain the Pareto front. The optimal reference point distance method was then used to optimize the protective structure parameters. The integrated protective system was designed and fabricated using low-temperature crimping and threaded fastening techniques. ANSYS simulation results demonstrate that the optimized protective structure achieves a 71.4% improvement in overall shielding performance. The protective structure guided by the optimization algorithm based on the shielding model improves a 4.1% in overall shielding performance.关键词：electromagnetic railgun;stress wave shielding;electromagnetic wave shielding;NSGA-II algorithm;structural simulation18|1|0更新时间：2026-05-19 - 摘要：In federated learning-based network intrusion detection systems， model structural heterogeneity and class-imbalanced data distributions often coexist， making it difficult for conventional parameter aggregation or simple knowledge distillation methods to simultaneously achieve high global model performance and strong local adaptability. To address this issue， this study investigates efficient knowledge fusion under heterogeneous federated learning settings and proposes a federated class-wise bidirectional knowledge distillation method for network intrusion detection， termed FedCKD. During the global aggregation stage on the server， a class-wise learnable weight matrix is introduced to perform weighted distillation of client model predictions across different attack categories， enabling fine-grained fusion of heterogeneous model outputs. During the local update stage on the clients， an attention-based distillation mechanism constructed from class-wise F1-scores is employed to enhance feature learning for minority and hard-to-classify classes under the guidance of the global model， thereby alleviating the impact of class imbalance on model performance. Experimental results on the public CICIDS2017 and CIDDS-001 network intrusion detection datasets show that， compared with FedAvg， FedMD， FedHe， and HFedCKD， FedCKD improves the macro-average F1-score of the global model by approximately 0.012 to 0.045， and increases the F1-score of minority attack classes in local client models by approximately 0.030 to 0.086， while maintaining stable convergence behavior and acceptable computational overhead. The results indicate that FedCKD enables effective modeling of multi-class attacks in heterogeneous federated learning environments without requiring unified model architectures， and is applicable to network intrusion detection tasks characterized by model heterogeneity and class imbalance.关键词：network intrusion detection system;federated learning;model heterogeneity;knowledge distillation19|1|0更新时间：2026-05-19
- 摘要：A lightweight network intrusion detection model， termed MobileViT-RMF， was proposed to address several limitations in existing traffic-visualization-based intrusion detection methods， including insufficient representation of temporal correlations in traffic data， limited feature characterization capability， and restricted detection accuracy under lightweight model constraints. The proposed method combined the Gramian Angular Difference Field （GADF） with a Residual Multi-grain Focus （RMF） module to improve both traffic representation and feature extraction. Firstly， one-dimensional network traffic feature sequences were converted into two-dimensional GADF images with spatiotemporal correlations， so that the evolutionary characteristics of traffic behavior and the discriminative differences among traffic categories could be more effectively preserved in the image space. On this basis， the RMF module was embedded into the lightweight MobileViT backbone to strengthen local key-feature extraction and global contextual modeling through a multi-granularity feature focusing mechanism， thereby the discriminative capability of the model for complex traffic images was enhanced. Experimental validation was conducted on the CICIDS2017 and UNSW-NB15 public datasets. The proposed model achieves a detection accuracy of 99.75% on CICIDS2017， which is 2.74 percentage points higher than that of the baseline MobileViT_V3_xxs model. On UNSW-NB15， the peak accuracy reaches 99.89%， indicating favorable cross-dataset detection performance. These findings suggest that the combination of GADF-based traffic image representation and RMF-based feature enhancement can improve the representation quality and classification performance of network traffic images while preserving the lightweight nature of the model. The proposed approach provides a feasible idea for the design of lightweight network intrusion detection models.关键词：intrusion detection;lightweight network;image classification;MobileViT16|1|0更新时间：2026-05-19
- 摘要：A general parking path planning method was proposed to address the limitation that traditional Hybrid A* often failed to strictly satisfy vehicle kinematic constraints in parallel， vertical， and oblique parking scenarios. The parking space constraint was formulated as a convex optimization problem via the Lagrange dual function， enabling the computation of a globally optimal path under kinematic feasibility. To overcome the low efficiency of nonlinear programming， a warm-start strategy was adopted： the initial path was generated using Fault-Tolerant Hybrid A*， the reference velocity was derived from trajectory curvature， and the dual variables were initialized from the constraints. The final solution was obtained by solving the transformed nonlinear equations. Simulation studies on three parking scenarios verify the versatility and optimality of the proposed method.关键词：autonomous parking;path planning;convex optimization;warm start17|1|0更新时间：2026-05-19
- 摘要：The reasoning speed of convolutional neural network accelerator is limited by memory bandwidth and on-chip storage resources， so it is difficult to give full play to the advantages of parallel computing on FPGA platform with less RAM resources. To solve this problem， this paper proposed an accelerator structure which adopted the memory access optimization strategy of “peak shift” calculation and bus dynamic allocation. Firstly， hierarchical computation and ping-pong caching were used to reduce the number of “peak” access transactions. A flexible DMA module was designed to realize the dynamic allocation of the feature and weight memory access bus to improve the bus bandwidth during “peak” time. Secondly， the multiplicative array was reused to maximize the DSP utilization by changing the data stream with a fixed multiplicative array. Then， the software and hardware collaboration and highly streamlined design method were adopted to make the data flow from the bottom to the top of the accelerator form a full streamlined structure in the time line. In addition to the phase-locked loop and large RAM， the acceleration module was designed in HDL and source language， and can achieve high speed operation of 300 MHz when the XCZU3EG platform resource utilization exceeds 80%. The experimental results show that MobilenetV2-1.0-256 achieves 125 GOPs throughput on the proposed acceleration structure， which is close to the upper bandwidth limit of the memory access bus. Inference speed of the proposed accelerator is 7.50 times of mobile ARM CPUs and 1.21 times of high-performance CPUs. Compared with desktop GPUs， the energy efficiency ratio is 3.5 times. Compared with the same type of accelerator on other FPGAs， it has advantages in performance density and energy efficiency ratio.关键词：field programmable gate array （FPGA）;hardware accelerator;convolutional neural network（CNN）;memory access optimization;software and hardware cooperation10|1|0更新时间：2026-05-19
- 摘要：Based on the characteristics of AIDS transmission， this paper subdivided the susceptible population into susceptible people with high-risk behaviors and ordinary susceptible people， and considered the impact of drug blockade on AIDS transmission， and established a dynamic model of
- 摘要：A SIS infectious disease model with medical resources in the adaptive network was established， and the influence of adaptive behavior and medical resources on the spread of disease was studied. The system was closed by using the triple approximation formula under the Poisson distribution. The basic reproduction number
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