Abstract:The latest research advances in tool type and technology strategy on machining quality during hole making of FRC are summarized. Firstly， the classification， characteristics and aerospace application of FRC are introduced， as well as the machining defects and problems of FRC hole making using traditional twist drill and technology are introduced. Secondly， the formation and evaluation of delamination defects in the hole making of FRC are summarized. Thirdly， from the two aspects of tool type and technology strategy of hole making， the research advances in hole making quality of FRC are summarized， as well as the novel cutting tool， technology and strategy to improve the machining quality of FRC are summarized. Finally， the machining quality effects of tool type and technology strategy on hole making of FRC are analyzed and summarized， meanwhile the future development trend and possible research direction are prospected.

Abstract:With the advent of the 5G era， the problem of electromagnetic pollution is becoming increasingly serious. Electromagnetic shielding is an effective method to solve electromagnetic pollution， which has become the focus of attention. Conductive nanoparticles have excellent electrical conductivity and unique physical properties， and their resin matrix composites can be used as electromagnetic shielding materials with lightweight and high electromagnetic shielding efficiency. In this paper， the electromagnetic shielding properties of resin matrix composites containing one-dimensional conductive nanoparticles （such as carbon nanotubes and silver nanowires） and two-dimensional conductive nanoparticles （such as graphene and MXenes） are summarized， and their development trend is further prospected.

Abstract:The research of nickel zinc ferrite microwave absorbing material is reviewed. A comprehensive summary of nickel zinc ferrite absorbing materials is conducted from aspects of magnetic performance， the influence of formula on absorbing performance， and the influence of composite with other materials on absorbing performance. The comparison is made with our research situation， hoping to provide support for the development and application of nickel zinc ferrite absorbing materials.

Abstract:Aircraft laser paint removal might cause potential damage to the 2024 aluminum alloy skin. It was necessary to explore the effect of laser parameter changes on the surface of the matrix material， in which the pulse width had an important impact on the laser-material interaction and material damage characteristics. In this paper， the temperature rise characteristics of the aluminum alloy surface exposed to laser with different pulse width were simulated and analyzed by COMSOL Multiphysics software， and the ISO 11254 1-on-1 laser damage threshold test method was used to reveal the influence of pulse width on aluminum alloy damage threshold. Furthermore， the micro-morphology， diameter and depth of ablation pits were further analyzed under different pulse widths. The results show that the peak temperature of aluminum alloy surface decreases with the increase of pulse width. When the pulse width increases from 150 ns to 240 and 330 ns， the damage threshold of aluminum alloy increases from 9.96 J/cm² to 11.24 and 12.66 J/cm²， respectively. The laser energy density reaches the damage threshold， the 3 μm thick oxide film is completely damaged， which destroys the surface integrity of the aluminum alloy. The diameter and depth of the ablation pits increase with the increase of the pulse width， and the depth is more affected. This research can provide a reference for the selection of pulse width for the interaction between laser and materials.

Abstract:In order to study the effect of thermal expansion coefficient of mold materials on the curing deformation of composites， the hot pressing tank curing process of composite parts was focused. To address the problem of thermal curing deformation of composite parts caused by the inconsistency of thermal expansion coefficients between composite forming mold materials and composite parts， the interaction relationship between molds and composite parts was studied， and a theoretical model of mold on the curing deformation of composite parts was derived. A numerical simulation model of the mold temperature field was established using simulation software such as ABAQUS， and the simulation data of mold thermal deformation was compared and analyzed with the experimental data of composite part deformation. The results show that the deformation values at different positions of the mold surface of different materials are independent of the structural characteristics of the surface but are related to the size of the surface. The greater the difference in expansion coefficient between mold materials and composite materials， the greater the deformation of composite parts.

Abstract:The cyanate ester resins were prepared by adding different low content epoxy AG80 and benzyl dimethylamine （BDMA）. The microstructure， curing heat effect， vacuum outgassing properties， mechanical properties， water absorption and thermal weight loss of low content epoxy modified cyanate ester resin were analyzed. The experimental results show that AG80 epoxy resin with mass fraction of 5% and 8% can effectively promote the curing degree of cyanate ester， reduce the number of uncured small molecules， and improve the vacuum outgassing properties of cyanate ester resin under the action of catalyst BDMA. BADCy-1 has the best vacuum outgassing properties and moisture resistance， in which the total mass loss （TML） and collected volatile condensable material （CVCM） are 0.41% and 0.03%， respectively， and the water absorption is reduced by 15%. The mechanical properties of BADCy-2 are optimized， and the tensile strength and flexural strength are improved by 23% and 20%， respectively. At the same time， the heat resistance of the material decreases with the increase of epoxy resin content.

Abstract:This paper proposed to prepare a composite nanometer self-lubricating diamond grinding wheel， and conducted a grinding test of SiC ceramics， and analyzed the influnence of the composite nanometer self-lubricating diamond grinding wheel with different mass fractions of composite nanoparticle on grinding performance. In this paper， nano-MoS₂， TiO₂ particles were selected as the filling materials， and a composite nano self-lubricating diamond grinding wheel and a traditional grinding wheel were used for comparison grinding experiments. At the same time， the lubrication mechanism of the composite nano-self-lubricating diamond grinding wheel was studied. The results show that the self-released nanoparticles of the grinding wheel effectively participate in the lubrication of the grinding area， reduce the normal and tangential force on the grinding wheel， and improve the surface quality of the workpiece. In the grinding depth of 2-8 μm，the specific performance is that the normal and tangential grinding forces of the composite nano self-lubricating diamond grinding wheel are effectively reduced by 18.6%-38.7%， 11.2%-28.6%， and the surface roughness is reduced by 13.9%-41.5%. When the mass fracture of composite nanoparticles is 8%， the performance and surface quality of the workpiece are the best.

Abstract:TA7 （α phase）， TB6 （β phase） and TC4 （α+β phase） alloys were selected for cutting experiments， and the right-angle cutting model was designed， and the cutting speed was the only variable to analyze the cutting force changes of the three kinds of titanium alloys during the cutting process. The cutting experiment results show that the cutting force of β phase titanium alloy is much greater than that of α phase titanium alloy and α+β phase titanium alloy during the cutting process. The cutting force of the three titanium alloys increases first and then decreases with the increase of cutting speed during the cutting process， reaching the maximum when the cutting speed is 50 m/min. The sawtooth chips are collected and observed， and the formation mechanism is analyzed， and it is observed that with the increase of speed， the chips change from banding to sawtooth. Based on the cutting force data and chip morphology changes of the three kinds of titanium alloys with the change of cutting speed during the experiment， the two formation factors of adiabatic shear have an important impact on the cutting force and chip morphology in the process of cutting from low speed to high speed.

Abstract:To investigate the effect of different surface treatments on the bonding strength of Al-Li alloy， the sandpaper grinding， copper chloride etching， sandblasting and phosphoric acid anodizing methods were applied， and the microstructure， roughness， wettability and strength of adhesive joints of different modified surfaces were compared and analyzed. The results show that the surface wettability and bonding properties of Al-Li alloy are improved after surface treatments. Compared to untreated samples， the surface free energy of samples treated with sandpaper， copper chloride etching， sandblasting， and PAA increase by 26.7%， 48.8%， 52.9%， and 71.1%， respectively， and the corresponding adhesive joint strength increase by 152.7%， 204.1%， 285.1%， and 413.5%， respectively. The porous oxide film structure constructed by PAA is more conducive to the penetration and adhesion of adhesive on the sample surface. The surface wettability and bonding strength are significantly improved， with a maximum bonding strength of 38 MPa.

Abstract:In order to achieve high efficiency and high quality friction stir welding of complex-structured aluminum alloy products forming， the research on flexible welding systems was carried out based on the combination of KUKA heavy duty robot and new friction stir welding technology. Through self-developing multifunctional friction stir welding host unit and test equipment， the robot flexible welding dedicated control system was developed to realize integration control. Based on this research， the research on microstructure and properties of the joint in the plate welding test piece and the friction stir welding test verification of the space curve trajectory were carried out. The results show that the heavy-duty robot friction stir welding system can stably weld 6 mm thick 2219 C10S aluminum alloy plate test piece and 3 mm thick S-shaped space curve welding test piece. When the stir head rotation speed n is 800 r/min， the welding speed v is 200 mm/min， the mechanical properties of the test piece joint such as tensile strength and elongation are good. Ultrasonic phased array and X-ray inspection are carried out on the welding seam of the sample， and no excessive defects such as holes and cracks are found in the weld， which verified the applicability of the robot friction stir welding system and process method.

Abstract:Cold chain devices with ultra-flexibility and high thermal conductivity had important engineering value and strategic significance in the fields of infrared focal-plane refrigeration for space loads， active and efficient heat transfer， and uniform temperature thermal management. A new graphene film cold chain was proposed， and thermal collaborative design and experimental research were carried out for this prototype. The effects of cold chain length， lap length， size， and the number of end columns on heat transfer of the heat transfer belt were explored. Meanwhile the effects of cold chain length， thickness， and width on its vibration transfer were verified.The results show that solder filling has a significant effect on the improvement of the thermal conductivity of cold chains. Increasing the lap length and the number， the diameter of the end columns can effectively improve the thermal conductivity of the cold chain. Further， the decrease in thickness， the increase in the width and the ratio of width-thickness can increase the response amplitude of the cold chain end. This study is prone to provide a fundamental reference for the design and selection of cold chains with both high flexibility and high thermal conductivity.

Abstract:To address the quality problems caused by the debonding defects of the solar array substrate during the manufacturing process， the phase-locked infrared thermal imaging detection research was carried out. By designing a reference block that was consistent with the debonding type of the battery array substrate， the influence of the uniformity of the adhesive content and the density of the carbon fiber mesh on the detection image was analyzed， and the real debonding defect feature information and parameters were obtained， so as to realize automatic defect screening. The test results show that phase-locked infrared thermography can effectively detect the debonding defects of the solar cell substrate， effectively improve the product detection efficiency and reduce the work intensity of the inspectors.

Abstract:Aiming at the technical difficulties of the cantilever scanning corner mirrors assembly of spaceborne Michelson interferometer， such as multi-dimension， high precision， difficult detection and etc.， a method of "vector analysis + precision micro-adjustment" was proposed， which included establishing the installation and detection benchmark， simplifying the angle mirrors to a spatial point vector， adopting the adjustment sequence of "first method to back plane" and using special precision micro-motion device， etc. And finally the high-precision adjustment of the spatial multi-degree-of-freedom angle mirrors assembly was realized. After the adjustment， the symmetry of the vertex position of the angle mirrors reaches 0.008 mm， which is superior to the design accuracy of 0.01 mm. The adjustment accuracy is improved effectively and the adjustment cycle is shortened.