Aiming at the problems of high surface roughness, poor forming quality, and post-processing such as machining after printing of laser deposition manufacturing (LDM) formed parts, the forming platform is built independently to print thin-walled parts with different inclination angles by using the process method of “small spot, small layer thickness and small powder particle size”. Based on the principle of layered slicing of additive manufacturing, the theoretical surface roughness prediction model of typical thin-walled parts under different geometric characteristics is given. On this basis, the control strategy of surface roughness of laser deposition manufacturing parts is proposed. The results show that it is feasible to obtain the prediction model of the mathematical model by rotating and translating the surface roughness prediction model of the component by combining the fusion lap with the step effect. The main parameters of the roughness prediction model are the fusion lap offset, the interlayer lift and the tilt angle. When the fusion lap offset is 0.5 mm, the upper surface roughness of the part is 10.5 μm. When the interlayer lifting amount is 0.15 mm, the surface roughness of the vertical side is 12.214 μm, and the theoretical error of the surface roughness of the inclined side with the forming angle of 60° is the largest. The powder adhesion phenomenon is the main reason for the large error.

Lightweight composite sandwich structures consist of thin and strong panels and lightweight porous cores, and diversity of their core structures drives the development of sandwich structures. In nature, various types of organisms have formed the most suitable biological structure for their survival and reproduction during the long-term evolution process, in which the high-strength structure has inspired researchers to carry out biomimetic design of sandwich structure cores. In this paper, research status of biomimetic core structure of water animals, land animals, flying animals, as well as plant fruits, roots, stems, and leaf veins is reviewed, and design concepts of biomimetic composite sandwich structure cores and topologies are described. The improvement of mechanical properties of bionic composite sandwich structure and its application in related engineering are introduced. Finally, based on the current development status of bionic composite sandwich structures, scientific challenges are presented and outlook is given.

In this paper, the grid structure parameters of complex rotary body are optimized, with the maximum load-mass ratio as the optimization objective and the geometric parameters and number of ribs as the design variables, the evaluation index of load bearing efficiency of the model structure was determined, and the single factor analysis was carried out by using the buckling analysis of ABAQUS. The number of longitudinal ribs, width of longitudinal ribs and height of longitudinal ribs have significant effects on the model’s bearing efficiency. The number and width of ring ribs have a low influence on the model’s bearing efficiency. The factor range for orthogonal test is obtained by analyzing actual manufacturing conditions. The orthogonal table L₁₆(4⁵) is designed by using the principle of orthogonality in mathematics. An orthogonal test scheme suitable for complex grid structure is designed. Through numerical simulation, 16 groups of test results were obtained, and the test results were analyzed by range analysis. It is found that the order of influence degree of each factor on the target value is: Longitudinal rib width>rib height>number of longitudinal rib>number of ring rib>ring rib width, and the optimal parameter combination is obtained. Finally, the optimal parameter combination is verified by experiment, and the difference between the theoretical value and the actual value of the maximum load of the rotary body using the optimal parameter combination is found, and the reason of the difference is analyzed.

The as-cast microstructures of TiAl alloys have low strength and poor plasticity due to their coarse grains, and they must be refined by heat treatment. The microstructure evolutions of Ti–47Al–2Cr–2Nb alloy castings after different heat treatments were studied using OM and SEM. The heat treatments of duplex (DP) and nearly lamellar (NL)  microstructures were optimized and established, which realized the grain refinement. The mechanisms of grain refinement were revealed. The results show that the DP microstructure heat treatment of 1185 ℃/6 h/furnace cooling and the NL microstructure heat treatment of 1185 ℃/6 h/furnace cooling + 1330 ℃/0.25 h/furnace cooling can refine the as-cast grain size by 75.51% and 40.21%, respectively. The grain refinement mechanism of DP microstructure heat treatment is that a large number of γ grains precipitate inside the lamellar colony grains and break the original coarse lamellar colony grains. The nucleation of γ nuclei in the lamellar colony grains comes from Al element segregation and continuous coarsening of γ lamellae. The grain refinement mechanism of NL microstructure heat treatment is that the γ→α transformation takes place in the α single phase region for a short time which destroys the original coarse lamellar colony grains, and the equiaxed γ grains can pin the growth of α grains, so that the lamellar colony grains formed after cooling are smaller.

Resin film infiltration (RFI) process is a widely used integrated manufacturing technology in composite material molding, which is very suitable for manufacturing large, reinforced, and complex aviation structural components. This article selected a typical composite hat stiffened panel, completed the integrated design of the fixture structure and process flow, and simulated the resin penetration process under different resin film positions and curing pressures. Based on the simulation results, reasonable resin film positions and curing pressures were selected. Finally, process experiments were completed according to the selected scheme, and the apparent quality and non-destructive testing of the typical parts were qualified, verifying the effectiveness of RFI integrated design and  simulation analysis for hat stiffened panel.

Aluminum alloys, known for their low density and high specific strength, are widely used in aerospace and a utomotive lightweight applications. Integrated die casting enables the production of large, complex, thin-walled castings, effectively aiding in weight reduction and range extension for aircraft and automobiles. This paper provides a comprehensive review of the development of large integrated die casting for aluminum alloys. It analyzes the compositional design of non-heat-treatment aluminum alloys and highlights the characteristics of the developed alloys. Additionally, it introduces the progress of domestic and international development of large integrated die casting machines and molds. The current state of numerical simulation research is summarized regarding mold filling, solidification, defects prediction, microstructure, thermal stress, and fatigue life prediction of integrated die casting parts. The paper concludes with a discussion of future developments in integrated die casting technology.

The integral impeller with uniform-section blade is widely used in engines of aerospace and weaponry. The electrochemical trepanning machining has obvious advantages in decreasing the machining cost and improving the machining efficiency of uniform-section blade. In order to solve the stability problem in the electrochemical trepanning machining process of narrow channel integral impeller, the composite cathode and tooling fixtures with closed flow field were designed innovatively, and the electrochemical machining verification test was carried out. The results show that the composite cathode can effectively solve the instability problem caused by the large difference between the vane spacing of the blade tip circle and the blade root circle. The closed flow field improves the distribution uniformity of electrolyte pressure and electrolyte velocity in the machining region. The surface quality of blade is high, and the machining process is stable, which lays a technical foundation for the high quality and efficient processing of the narrow channel integral impeller.

The effects of P/Al ratio and Cr/Al ratio on the phase composition, microstructure, mechanical properties and dielectric properties of quartz fiber-reinforced phosphate composites were investigated. The results show that the phase composition of the phosphate matrix is mainly composed of Berlinite phase, low-temperature quartz type AlPO₄ and  unreacted α–Al₂O₃, and the composition ratio and microstructure of the matrix phase are influenced by the P/Al ratio and Cr/P ratio. When P/Al=4.1 and Cr/P=0.04, the composites have the best mechanical properties, with tensile strength of 108.6 MPa, bending strength of 135.3 MPa and fracture toughness K_ⅠC of 6.6 MPa·m^1/2, and the composites exhibit the plastic fracture characteristics of weak bonding interface. It is analyzed that at this time the matrix contains more Al(H₂PO₄)₃ phase with good bonding properties, and the matrix exhibits a smooth planar-like structure, which is conducive to the formation of a complete and continuous good interfacial layer between the matrix and the fiber. In addition, the dielectric properties of the materials are greatly affected by the Cr content, except for Cr/P=0.08 materials, the dielectric properties of the prepared materials can meet the performance requirements of high-temperature wave-transparent materials, and have a broad application prospect.

Solar-powered drones are equipped with wings that possess typical characteristics of low wing loading, high flexibility, and high aspect ratio. As the main load-bearing structure of the wing, the wing spar has very strict requirements on its load capacity and weight. The key technical issues in the research of solar-powered drone spar structures were how to improve the load efficiency of the spar structure, achieve a comprehensive balance between load capacity and weight, and realize the integrated design and manufacturing of large-scale composite material spars. This paper proposes a fast structural configuration selection and optimization design method for the composite material spar design of solarpowered drones. This method determines the design parameters by calculating the load capacity of the spar cross-section, and considers the ply symmetry, strain constraint, and stability constraint at the same time. It can avoid building a fullscale finite element model and performing iterative calculations at the scheme stage, thus improving the  esign efficiency of the spar structure. Secondly, for the large-scale composite material tubular spar structure, a dedicated molding method is proposed, which realizes the integrated manufacturing of the spar and ensures the quality of the molded parts, providing a reference for the manufacturing process of similar large-scale composite material structures. Finally, a static test of a 2 m-scale tubular spar is carried out, and the strain results of the typical cross-section are within 10% error of the design results, verifying the applicability of this fast optimization design method.

It is of great significance to study the influencing factors of the surface topography of nickel-based superalloy GH4169 processed by end-milling to control the surface roughness and improve the machining quality of GH4169. Based on single-factor end-milling experiments, the effects of milling speed, milling depth, feed per tooth and milling width on surface roughness and 3D surface topography were investigated. The results show that the influence degree on surface roughness is as follows: Feed per tooth, milling width, milling speed, milling depth, etc. The machined surface mostly presents the texture of vertical and horizontal phase, and the degree of influence on the surface texture depth is as follows: Milling speed, milling depth, feed per tooth, milling width; Combined with the processing surface roughness and 3D surface topography, the best processing parameters are: Milling speed V=100 m/min, milling depth t=0.1 mm, feed per tooth f_z=0.025 mm/z, milling width a_w=5 mm.

Aiming at the edge-milling distortion problem of the composite thin-walled workpiece, which is clamped on the flexible tooling system, the milling process is simulated by finite element method with commercial software ABAQUS. The influence of POGO column spacing, POGO column to edge margin, and the main fiber angle of composite thin-walled parts on the milling deformation is studied. A method for predicting the deformation of thin-walled parts during flexible clamping is proposed. This method can effectively predict the deformation of thin-walled parts under the influence of parameters such as spacing, margins, and angles. The method has a maximum error value of 3.6% for the prediction of the edge weight deformation of thin-walled parts, and a maximum error value of 2.70% for the prediction of the external force deformation of the edge of the thin-walled parts.