The mechanical properties of the 7xxx series aluminum alloy deposited specimens are low due to the uneven microstructure and element segregation in the process of wire and arc additive manufacturing (WAAM). In order to solve this problem, the 7075 aluminum alloy thin-walled specimens deposited by WAAM were subjected to solid solution + artificial aging heat treatment (T6 state). The microstructure evolution and mechanical properties before and after heat treatment were investigated. The results showed that the grains in the as-deposited specimen were surrounded by eutectics with network-like structure, and the elements of Zn, Mg and Cu were concentrated at the grain boundaries, resulting in the element segregation. After T6 heat treatment, most of the eutectics were dissolved. Moreover, the unevenness of the element distribution was significantly reduced. Compared with the as-deposited specimens, the tensile strength and elongation of T6 specimens were improved. The value of tensile strength increased from (279.4±5.3)MPa to (493.9±10.2)MPa, and the elongation increased from 3.78 %± 0.35% to 9.66% ± 1.70%. The tensile fracture surface of T6 specimen was densely covered with dimples. Therefore, the fracture mode was ductile fracture.

Electron beam melting (EBM) has the advantages of high forming speed, high efficiency, and no pollution in vacuum environment. It is suitable for forming Ti–6Al–4V titanium alloy and has been widely used in aerospace, biomedical and other fields. However, the internal pores, rough surface and residual tensile stress of the asbuilt EBM Ti–6Al–4V titanium alloy components seriously affect the fatigue performance of formed part. Through optimization of printing parameters and post-treatment processes, such as hot isostatic pressing and surface treatment, the fatigue performance of EBM formed parts can be significantly improved. The forming process, microstructure, mechanical properties and typical application status of EBM Ti–6Al–4V titanium alloy are reviewed. The factors affecting fatigue performance are discussed, and some post-treatment methods to improve fatigue performance are summarized. Finally, the future development prospect of EBM technology is prospected.

In this paper, the non-traditional laser beam of selective laser melting (SLM) is taken as the object of investigation, the principle of non-traditional laser beam shaping and its SLM equipment are introduced, the elliptical Gaussian laser beam, flat-top laser beam, inverse Gaussian laser beam and micro Gaussian laser beam are classified. Besides, the effects of different laser shape types on the thermal history, microstructure and defects of the products during SLM process are summarized. The study of integrated beam shaping devices and non-traditional laser beam SLM printing reveals that elliptical Gaussian laser beam printing allows for convenient microstructure control and improved equiaxed crystal ratios because of the change of beam ellipticity, which gives the product different heat profiles in different parts. Flat-top laser beam, because of uniform energy distribution, enables the particles melted in conduction mode, which can effectively suppress the generation of cracks and spatters and obtain products with sound surface. Inverse Gaussian laser beam, because of the wide process window, is suitable for production at high scan speeds and high laser power, which can maximize the productivity of SLM. Micro Gaussian laser beam can refine the grain and improve the accuracy of the product because of the large temperature gradient and fine beam diameter during SLM. Finally, this paper provides an outlook on the future development of non-traditional laser beams’ SLM based on the aforementioned analysis and discussion.

The rapid and free forming characteristics of laser melting deposition (LMD) bring new design ideas andmanufacturing methods for the development of aeronautical components. In this paper, the microstructure and mechanical properties of laser melting deposited (LMDed) titanium alloys and titanium matrix composites (TMCs) are summarized and analyzed, including the effects of deposition parameters, heat treatment and the types and content of reinforcements on the microstructure and mechanical properties of LMDed components. It is found that the deposition parameters directly affect powder melting, the fusion quality and the microstructure of components after deposition, which influences the microstructure and properties of deposited components. By appropriate heat treatment, the forming stress could be reduced and the microstructure and properties of components can be modified. The reinforcement content is closely related to its solubility in the matrix, which makes TMCs show different microstructures and mechanical properties compared to titanium alloys. Finally, the application of LMD technology in the manufacture and repair of titanium alloy and TMCs components are analyzed and concluded.

With the increasing demand for a high thrust-to-weight ratio and highly efficient aero-engines, the development of engine blades is moving towards a complex hollow structure, and therefore places greater demands for ceramic core with high-performance complex structures. Meanwhile, the additive manufacturing technology, based on the principle of lithography, can realize the preparation of ceramic cores with high precision, high speed and excellent comprehensive performance without metal molds. However, the state-of-the-art ceramic core preparation processes, based on lithography-based additive manufacturing, still faces several problems in controlling dimensional accuracy, optimizing the binding, sintering process and controlling crack deformation. Therefore, the research progress of the preparation and sintering process of lithography-based ceramic slurry is discussed, focusing on the comprehensive performance, based on the introduction of the principle and characteristics of lithography-based additive manufacturing technology. At last, the application examples of light-curing cores/shells in the precision casting of aero-engine blades and further application prospects are also introduced.

Laser additive manufacturing (LAM) technology can achieve the large-complex components of ultra-high strength steel with high performance, and can also be used for rapid repairing the damaged parts, which is widely used in aerospace and other fields. This paper introduces the forming characteristics of laser additive manufactured low alloy high strength steel, and the influence of the heat accumulated on the microstructure of the LAMed low alloy high strength steel. The mechanism of the microstructure and heat treatment on mechanical properties of LAMed low alloy high strength steel and the application of LAM in repairing ultra-high strength steel are described. The development trends of LAM ultra-high strength steel are prospected.

In order to solve the problem of incomplete polishing of the irregular waveguide inner sphere by abrasive flow polishing, the copying mold cores were set to guide the abrasive flow through the inner sphere and polish it. Fluid simulations for channel models formed by different copying mold cores and waveguide inner cavities have been carried out by Fluent, through which the flow velocity, the pressure and the wall shear stress of the equivalent wall have been contrasted and analyzed. The simulation results revealed that the machining quality of inner sphere is better with the increase of the ball diameter of the mold core. The abrasive flow polishing test has been carried out with a 9mm ball diameter copying mold core, after that the surface roughness S_a of the waveguide inner sphere is reduced from 5.07μm to 0.51μm and the surface quality is improved significantly.

Zonal safety analysis (ZSA) is considered as the analysing and checking processes taken place on a physical prototype to reduce the function performing risks of overall aircraft and systems from physical integrations like assembly and maintenance, including coordination and compliance checks between structure and systems, and between system and system. As the introduction of digital design, part of ZSA analysis is also trying to apply based on a digital mock-up. In civil aircraft design, SAE Aerospace Recommended Practice 4761(ARP 4761) introduced the ZSA method, implementation steps and practice cases, and suggested to apply ZSA through all the development phases. Aircraft final assembly stage, with systems installation and test, is the main stage for function implementation of an aircraft as well as a major stage for introduction of the overall aircraft quality and safety characteristics. This paper presents the scenes and implementations towards integration of ZSA and aircraft final assembly engineering activities. It introduces the classical common cause analysis tool ZSA, which is considered to be used for design, to the complicated final assembly integration process. With the help of its structured analysis and inspection methods, this research connects system functional block diagram, fault tree analysis (FTA), design failure mode and effects analysis (DFMEA), process design failure mode and effects analysis (PFMEA), and ZSA. This would reduce quality risks from final assembly significantly and contribute fewer potential hazards from assembly integration that result in aircraft system risks in flight test and operation phases.

Based on cold cathode electron emission mechanism, a gas discharge electron beam (EB) gun and its electron optics system had been designed. In order to meet long time work requirement, three-stage AC–DC topology circuit, the circuit of transformer primary side parallel connection and output rectifier circuit series connection to obtain high voltage, double closed-loop control and discharge protection had been adopted to manufacture a inverter power supply. The output beam current of gas discharge electron beam source, which adopted mentioned above technology, is up to –20kV/1500mA. The experimental results show that, when the inert gas is used as the discharge gas, the electron beam current of the gas discharge EB gun will decrease for a long time. When the air is used as the discharge gas, the output characteristic of low voltage and high current is shown. When airflow rate of He, Ar or air is less than 0.03L/min, the output electron beam current increases with acceleration voltage increased. When the constant acceleration voltage is given, the output beam current increases gradually with the He airflow rate increased. The voltage and current waveforms of IGBT bridges in the third stage AC–DC circuit are well accordance, which will meet the need of long time stable operation and high power output.

To study the influence of hydrogenation on deformation and cutting mechanism of TA15 alloy, tensile test and cutting experiment with different hydrogen content are performed to obtain the mechanical properties, cutting force and the differences in microstructure characteristics of serrated chip. The results show that the yield strength ratio decreases, the plasticity enhances with high hydrogen content and its working hardening is serious. Hydrogen promotes the thermal softening effect, and the higher hydrogen content, the lower critical cutting speed which causes the decrease of cutting force. The difference of plastic deformation characteristics in different regions can be observed in the serrated chip of the as-received and low-hydrogenated groups, the uniform plastic deformation exists in the serrated unit, and the local severe plastic deformation exists in the shear band, which verifies the occurrence of adiabatic shear. However, the microstructure with high hydrogen content has high consistency without local severe plastic deformation. The serrated chip morphology shows the feature of decreasing serration, so it can be inferred that the hydrogen improves the plasticity of the alloy and inhibits the local severe plastic deformation, which significantly improves the cutting performance of TA15 alloy.

Airborne laser weapon has the advantage of rapidity and accuracy of laser and flexibility of flight platform, it can greatly reduce the influence of dense atmosphere and improve the laser attacking efficiency by firing at high altitude, thus it draws a lot of attention as a new weapon. Aiming at several large airborne laser weapons developed in foreign countries, this paper mainly analyzes the aerodynamics layout of laser launchers and summarizes main principles of large airborne laser weapon’s aerodynamics layout. The characteristics of large laser launchers perpendicular or parallel to free incoming flow are studied, some suggestions on turret rectification are given.

Selective laser melting (SLM) additive manufacturing technology is commonly used in the manufacture of complex small parts in the fields of aviation, aerospace and weapons, such as grille, cavity structure, combustion chamber components, etc. In order to adapt to the manufacturing of large-size parts, the ideal scheme is to adopt segmented additive forming and tailor welded joint. In this paper, the electron beam welding (EBW) process of SLM formed TC4 titanium alloy is verified, the welding porosity defects and their reasons are analyzed, and the improvement effect of different welding processes on the porosity defects is discussed. After the process optimization, the number and distribution of porosities are analyzed. The results show that the number and size of porosities are greatly reduced, the quality of electron beam welding meets the requirements of HB/Z 198 for level I standard, and the joint shows good tensile and fatigue properties at room temperature. Through the analysis and research, the feasibility of the hybrid manufacturing technology of SLM and EBW in the field for aviation manufacturing is verified.