Significantly improving the absolute strength of low-cost wrought magnesium alloys is one of the key bottlenecks in the field of light alloy research. In this study, a new Mg–Sm–Ce–Mn alloy containing low content of light rare earth elements was designed based on phase diagram calculation, and an ultra-high strength of nearly 400 MPa was achieved by low temperature extrusion. The Mg–0.8Sm–0.4Ce–0.4Mn (EM10, mass fraction, %) alloy formed a  dual-configuration grain structure after low temperature extrusion, and showed a typical silk texture, and dynamically precipitated Mg₄₁(Ce, Sm)₅ and Mg₁₂Ce micron second phase. The lower extrusion temperature and the precipitation of high-density nano-second phases contributed to the refinement of the recrystallized grain size of EM10 alloy to about 0.93 μm, while a high density of residual dislocations remained in the uncrystallized region. The combined effects of fine grain strengthening, second phase strengthening, texture strengthening and dislocation strengthening lead to the yield strength of EM10 alloy can be as high as about 379 MPa, while maintaining the elongation of about 4.7%. Continuing to increase the content of Ce and Sm elements, more brittle micron-sized second phases will be introduced, which will impair the plasticity of the alloy. Therefore, a high-strength Mg–0.8Sm–0.4Ce–0.4Mn alloy was designed and prepared by low-temperature extrusion process and composition optimization. The relevant results can provide theoretical guidance for the preparation of low-alloying and ultra-high-strength wrought magnesium alloys.

Inconel 718 is commonly used in aerospace, automotive and medical equipment, but it is a typical difficult-to-machine material due to its high strength and low thermal conductivity, resulting in large cutting forces and high cutting temperatures. In this paper, the true stress–strain curve of Inconel 718 at room temperature was obtained by the split Hopkinson pressure bar experiment, and the thermal softening rate of the material at different temperatures was obtained by the high-temperature hardness experiment. The laser thermal conductivity experiment was used to obtain the specific heat capacity and thermal conductivity of Inconel 718 at different temperatures, and the actual deformation temperatures at different strains were calculated by combining the true stress–strain curves. The decoupling of strain and temperature is achieved by using the thermal softening rate to correct the true stress–strain curve in the variable temperature state to the stress–strain curve in the isothermal state. The above experimental results were fitted based on the Johnson–Cook and Power–Law constitutive models, and the results show that the fitting accuracy of the Power–Low constitutive model is higher at low strain rates, while that of the Johnson–Cook constitutive model is higher at high strain rates. Finally, the response mechanism of the mechanical properties of Inconel 718 material under the action of strain, strain rate and temperature alone are explored through finite element simulation, and it is found that the strain has the greatest influence on the stress, followed by the temperature, and the strain rate has basically no influence on the stress.

Hybrid reinforced aluminum matrix composites can integrate the advantages of each component and exert a synergistic reinforcing effect. CNTs/SiC_p reinforced Al–Cu–Mg aluminum alloy composite was prepared by vacuum sintering process, with the mass fraction of CNTs and SiC being 0.7% and 10%, respectively. Isothermal forging at 450 ℃, 460 ℃ and 470 ℃ was carried out with high deformation degree, and the influence of isothermal forging on microstructure and mechanical properties of composite was studied. It was found that the plastic properties of hybrid reinforced aluminum matrix composites after isothermal forging were obviously improved compared with sintered ingot, and the composites after 470 ℃ isothermal forging had the best comprehensive mechanical properties than sintered ingot, with an increase of 48% in tensile strength and 260% in elongation. After isothermal forging, the flocculation and slender SiCp in the matrix arranged along the flow line, which strengthened the tensile mechanical properties of the material. The research in this paper can provide a certain theoretical support for the subsequent development and application of new high-performance aluminum matrix composites in the future.

Continuous SiC fiber-reinforced titanium-based (SiC_f/Ti) composites are one of the key materials for future high-performance power devices. To address the problem that the axial loading of fibers and specimens in SiC_f /Ti composites often exists at a certain off-axis angle, the influence of the off-axis angle on the mechanical properties and failure mechanism of SiC_f /TC17 composites was investigated using room temperature tensile, finite element simulation and fracture characterization. The results show that a critical off-axis angle can be defined based on the mechanical properties, fracture morphology and stress distribution of SiC_f /TC17 composites, and its value is about 1°. The tensile strength of the composite specimens decreased with the increase of the deflection angle, and the decreasing rate of tensile strength increased when the deflection angle exceeded the critical value. The failure mechanism of the composite material is related to the off-axis angle. When the off-axis angle is smaller than the critical value, the specimen fracture consists of several flat sections, the degree of fiber pullout and interfacial cracking is low, and the fiber section is basically perpendicular to the axis, which is a typical positive stress fracture; when the off-axis angle is larger than the critical value, the degree of undulation of the fracture increases, and the phenomena of fiber pullout and interfacial cracking become more obvious, and some of the fibers start to appear shear fracture, indicating that tension-shear coupling plays an important role in fracture. Therefore, for the axial specimens of SiC_f /TC17 composites, the off-axis angle between the fibers and the specimen as a whole should be controlled within the critical value in order to obtain effective performance test data.

In recent years, high-entropy alloys (HEAs) have attracted extensive attention of researchers because of their unique design concept and excellent properties with multiple principal components. Laser additive manufacturing (LAM) can produce HEAs with ultrafine grain and multi-scale structure, accompanied with excellent mechanical properties. Moreover, the doping of interstitial atoms and the addition of reinforced particles are helpful to further improve the strengt and plasticity of the alloy. It also has broad application prospects in aerospace high-performance structural materials and other fields. In this review, the principles and characteristics of selective laser melting and laser directed energy deposition are introduced firstly. Then, the effects of interstitial atoms (C, B, N) and reinforced particles on the microstructure and mechanical properties of HEAs fabricated by LAM are summarized. Additionally, the strengthening and plasticizing mechanism of each interstitial atom and reinforced particle is analyzed. Finally, the future development trend of LAM highperformance HEAs is prospected.

The adhesive performance at the interface of metal/composite materials is typically assessed based on measures of interface strength and interface toughness. Exceptional interface strength ensures that the material remains free from delamination and cracking when subjected to stress loads, while excellent interface toughness enhances the energy dissipation during crack propagation. Investigations have revealed that increasing the adhesive contact area, enhancing the interface reactivity, and improving the wettability of the composite material can effectively enhance the interfacial bonding performance. Additionally, optimizing the size of interfacial nanoscale toughening particles to achieve mechanical interlocking effects, as well as designing ordered microstructures on metal surfaces to reduce interfacial stress and delay crack propagation, can significantly improve the interfacial strength and toughness in metal/composite material systems. Therefore, the latest progress in improving the interface bonding properties of metal/composite materials is described from three aspects: Interface strengthening, interface toughness and interface strengthening and toughening, and its future development trend is prospected.

In order to analyze the influence of different elements on the stability of high speed cylindrical grinding process with CFRP grinding wheel, the Timoshenko beam theory was used to conduct the dynamic analysis on the stepped workpiece. Combined with the dynamic characteristics of grinding wheel measured by impact test, the grinding stability analysis of the two-degree-of-freedom system between grinding wheel and workpiece in high speed grinding process was conducted. During the dynamic analysis of the stepped workpiece, it was found that the stepped feature of workpiece has a small influence on the dynamic characteristics whose error is lower than 2%. In the grinding stability analysis, it was observed that the grinding stability can be affected by both the speed difference of grinding wheel and the difference of cutting position. The closer the grinding position is to the center of workpiece, the lower the grinding stability is and it is easy to induce chatter. As for the position near the center support, the grinding stability will be influenced by the dynamic performance of workpiece and grinding wheel at the same time as the increase of workpiece stiffness. The effectiveness of the proposed analytical method has been proved by the grinding experiment. The experiment results also indicate that the stiffness difference of the workpiece in different grinding positions can affect the surface quality, and the increase of workpiece surface roughness can reach 51.6% due to grinding instability.

Aiming at the instability of the weaving angle of the fabric during the weaving process of the mandrel with large curvature and complex, proposed an optimal control method of weaving traction trajectory based on offset compensation model. Firstly, based on the convergent distance transformation of the unstable braiding stage, the prediction model of preformed braiding points is established. Secondly, the mandrel is discretized, the axis of each discrete mandrel is adjusted vertically through the dynamic braiding point plane, and the braiding feed length of each mandrel is corrected. The mandrel attitude is adjusted by using the unstable braiding stage in the process of changing cross-section of the mandrel, and the traction speed in the unstable stage is adjusted to reach the stable braiding state faster. The experimental results show that the trajectory optimization method can improve the preform weaving quality.

Accurately solve the cutter–workpiece engagement (CWE) of ball-end milling has become a key problem for its mechanical behavior. In view of the limitations of the existent CWE solution methods of ball-end milling, such as low efficiency, poor universality and weak engineering applicability, a CWE solution method based on homogeneous transformation matrix is proposed to realize its prediction and analysis. Firstly, in light of the analysis of geometric characteristics in milling process, the analytical equations of vertical CWE are deduced; Then, from the perspective of multi-body system theory, the milling posture parameters of ball-end milling are characterized as coordinate matrix by homogeneous transformation method, and its analytical expression under any posture is derived. Besides, the milling process is discretized in time domain to analyze the effective milling edge and its evolution process in CWE. On this basis, the experiment for ball-end milling force is carried out to verify the reliability and accuracy of the solution method and milling force analysis. The results show that the proposed method can simplify the solution process of CWE, and the prediction of milling force is reliable and accurate; The increase of rake angle or roll angle will reduce the milling time of cutting edge and reduce the average milling force in the milling cycle; A larger milling force can be obtained with a smaller rake angle.

In this paper, the finite element simulation of the influence of abrasive grain spacing and workpiece material properties on workpiece surface temperature in grinding process is carried out. The results show that the surface temperature of workpiece increases gradually during grinding process; in the grinding process, the workpiece surface temperature in single abrasive grinding is lower than that in multi-abrasive grinding and the increase with time is smaller; the larger the distance between the abrasive grains, the lower the surface temperature and the smaller the change rate with the grinding process; when the thermal conductivity is greater than 1 W/(m·K), the temperature decreases with the increase of thermal conductivity no longer obvious; the effect of specific heat capacity and density of workpiece on grinding temperature is similar. The surface temperature of workpiece decreases with increasing specific heat and density. When the specific heat capacity is greater than 200 J/(kg·℃) and the density is larger than 4000 kg/m3, the decreasing trend of the surface temperature of the workpiece with the increase of specific heat capacity and density is no longer obvious, and the increasing speed of the temperature with time is reduced.

γ–TiAl alloy is a kind of intermetallic compound material with great application potential. It was brazed by the designed filler as Ti–15.6Zr–11.0Cu–9.8Ni (mass fraction, %). The microstructure and element distribution of the joint were analyzed. The microhardness and strength of the joint were tested. It was found that the diffusion of Al to the interface was the main driving force for the formation of the interface. The Zr, Cu and Ni elements in the filler metal are mainly concentrated in the center of the adjacent interface. Due to the coarse grain structure and the high hardness of the grid structure, brazing fracture happened in the central part of the adjacent interface. Although there is a continuous Ti₃Al phase near the interface, its excellent plasticity and the moderate hardness were beneficial to transfer the force between the matrix and the interface. Thus this phase was benefit for the toughness of the joint. The tensile strength of joint reaches to 517 MPa at room temperature, and the strength coefficient is 0.816。