In order to enhance the performance and flexibility of EB-PVD machine, the topology circuit of three parts of AC-DC circuits, the technology of several circuits in series and parallel connection, and double closed loop control have been adopted to design high voltage power supply and filament heating power supply. The inverter power supply, filament heating power supply, EB-PVD gun, vacuum system and others control system were assembled to establish a set of EB-PVD test equipment. Besides the high voltage and the maximal EB current output have been detected, the current of filament heating power supply and the input waves of power transformers also have been measured. Through the series of tests, the results show that not only the maximum high voltage output is up to -30kV, but also the inverter power supply has a good constant voltage character during electron beam output. The maximum electron beam current is up to 2000mA at 150A filament heating current. These test results show that the inverter power supply has fine applicability for EB-PVD machine.

The welding residual stresses were investigated with both experimental and numerical simulation methods,and the mechanism of the reheat cracking in Ti2AlNb EBW joint was also discussed with inspections on the characteristics of the cracks and the microstructures evolution during the heat treatments. The results showed that the EBW weld center suffered tensile stresses in three directions. The longitudinal tensile stress was the dominating tensile stress, which is more than 1100MPa, the tensile stresses in tansverse and thick directions had small values, except the plate is thick plate. Compared with the straight welds, the circular welds had lower hoop tensile stress, while higher radial tensile stress, especially in the small diameter circular weld. The formation of the reheat cracks was responsible to the precipitation layer at the grain boundary and the higher tensile residual stresses. The cracks were created and propagated along the interface between the precipitation layer and the matrix. The precipitation appeared when heating up to about 700°C with the heating rate below a critical value.

Variable polarity tungsten inert gas arc welding (VPTIG) is widely used in the welding of aluminum and aluminum alloys, due to its low cost and high weld quality. In order to enhance the arc energy density and its penetration ability, a novel ultrasonic double-pulsed deep penetration VPTIG (DP-VPTIG) process was proposed in this paper. Al-Cu and Al-Mg series aluminum alloy plates were employed as base materials. The preliminary experimental results show that the stable process and good welding quality can be obtained when DP-VPTIG is employed to weld aluminum alloy plates, and also the precise control of weld penetration can be achieved by adjusting the pulsed current characteristic parameters. It is very significant and valuable to carry out the applicability and related theoretical study for the novel DP-VPTIG process, which can be employed in the welding fabrication of aluminum alloy plates and show a good application prospect.

Because of excellent creep resistances and fatigue properties both in medium and high temperature, the directionally solidified superalloy DZ125 alloy has been widely used as turbine blades and guide vanes in engineering. In this paper, the repairing process of DZ125 alloy was discussed. The results showed that there were many HAZ cracks formed by using common welding materials. Then a kind of now welding alloy was developed and after proper welding and heat treatments no cracks were found in the joints. The microstructures of the joints were also homogeneous and the tensile strengths of the joints were 90% of that of DZ125 alloy.

Compared with traditional welding methods, high-power laser welding is characterized by high efficiency and good welding quality, especially in the welding process of thick plates. However, it was found out in recent researches when the laser power increased to a certain level, the welding penetration won’t get deeper any longer due to the absorption,refraction and the scattering effect of the plasma plume. That is generated by the evaporation of metal, and to prevent the laser beam from entering the keyhole. Welding under subatmospheric pressure is regard as an effective method and has an impressive promotion on both welding penetration and porosity defects. The development of the high-power laser welding under subatmospheric pressure, as well as some relevant issues are summarized according to recent researches.

Basing on the CEL numerical simulation method, adopted by Pressure Independ Multiyield Material model, the welding temperature field for friction stir welding (FSW) process of 2A14 aluminum alloy at different rotating speeds and welding speeds was simulated by finite element method. According to the temperature distributions, the variation rule of pre-molten viscousness layer at the front of the rotating tool was analyzed. Compared the requirement of rheological layer with simulated thickness of pre-molten viscousness layer, joint quality under different welding parameters was predicted. Therefore, the reference of process parameters selection for 2A14 aluminum alloy FSW was proposed.

Surface Welding Residual Stresses of TC4 Ti-Alloy Weldments by Narrow Gap TIG Welding Before and After PWHT

31mm thick TC4 Ti-alloy plates were welded by magnetically controlled narrow gap TIG, the surface residual stress distributions were measured by indentation strain-gage method before and after vacuum post-welding heat treatment (PWHT). The results show that the levels of longitudinal and transverse residual stress is all high on the weldment surface. The residual stresses on the lower surface are little higher than that on the upper surface, especially for transverse residual stress. The residual stresses peak value of the weldment exists in the high temperature heat affect zone, which reaches 50%-60% of the material yield strength. After 650°C vacuum post-welding heat treatment, longitudinal and transverse stresses on the weldment surface are significantly reduced, maximum stress reduction is more than 50%, the residual stress peak value left on the surface doesn’t exceed 200MPa, and the original welding residual stresses on the surface go to redistribute.

Diffusion bonding solid-state additive manufacturing technology adopts the same idea as laminated objective manufacturing. Laminates fabricated by precision machining or chemical etching are aligned and diffusion bonded to form 3D complex structures. This forming method is the most mature solid-state additive manufacturing method in industrial applications. This paper reviews the key applications of the method for different materials in the fields of astronautics, aviation, nuclear, fine chemical industry, navigation, injection mold and etc. Furthermore, the development of diffusion bonding technology and equipment manufacturing in the future are forecasted.

According to the structural characteristics and mechanical characteristics of the main bearing beam of a certain type of helicopter, a full composite material main bearing beam structure has been developed. Feasibility analysis was carried out by theoretical calculation, the FEM analysis model of pipe beam was established by MSC.Patran/Nastran and the static strength analysis was carried out according to actual load and restraint condition. The results of structural strain and displacement were obtained and the strength test scheme was also designed. The static strength test of the pipe beam structure was carried out and the result shows that, the main bearing beam structure of composite material meets the requirement of strength design. Compared with the original metal material, the tubular composite material reduced the weight by 17.6%, which fully reflects the overall performance of tubular composite material has better bearing capacity and application, promotes the analysis and practical application of tubular composite material.

The aircraft assembly components are typical for large size and complex shape, which makes it need large data for outline inspection. The contradiction between the measuring accuracy and efficiency of the existing single measuring device or measurement field is outstanding. Thus, the digital combined measurement system, including a laser tracker,an articulated arm measuring machine and photogrammetric system, is constructed. Based on the coordinate transformation, the measurement information of multiple stations is unified into the global coordinate system. The measurement results of the component shape are obtained by comparing the measurement data model with the theoretical model, improving the measurement efficiency of the profile surface under the condition of ensuring the measurement accuracy. Taking the assurance of shape accuracy of the flap assembly process for an example, the validity and correctness of the proposed method are verified.

In order to meet the ERP (Enterprise Resource Planning) system of BOM (Bill of Material) data of all kinds of business needs, studying the internal BOM data, product data information is required in accordance with the requirements of the data format of ERP system. Based on the analysis and comparison of different definitions of materials list of design, manufacture, assembly process, combined with the enterprise BOM status, from the characteristics of data, business process design, construction and maintenance of BOM and other aspects were summarized in detail. Based on PDM (Product Data Management) system assembly BOM data analysis, the demand model of ERP system for the assembly BOM data is built.

Due to various types, multiple batches and high manufacturing accuracy for civil aircraft composites allowable value specimens, strict quality control is required during the manufacturing process to improve the acceptability of specimens. Huge amount of composites allowable value specimens are needed, and lots of parameters of each specimen should be inspected, so it is necessary to use reasonable inspect methods to increase efficiency. Based on author’s experience about composites allowable value specimens manufacturing, some manufacturing process quality control methods and inspection methods are refined, which provide references for subsequent manufacturing of composites allowable value specimens.

When using traditional subtractive machining method, the tool can not reach somewhere for some complex parts such as engine impellers, blisks. The machining process would be hard. Additive-subtractive hybrid machining method can be used to machine before obstacles formed, which is an effective way to machine complex parts. Therefore, a hybrid manufacturing process planning algorithm should be researched. In order to validate the feasibility of the algorithm,an additive-subtractive-integrated hybrid manufacturing validation platform based on 5+1 axes is built in this paper. A small engraving machine is used as the base of the platform. X, Y, Z are three translational axes and B, C in the cradle platform are rotation axes, which construct the five-axis system. An additional axis controls feeding of 3D printing extruder. A mechanical device is designed, in which a guide mechanism is used to integrate 3D printing extruder and spindle of the engraving machine. Mach3 six-axis CNC system is used to control the movement of each axis. By this way, an additive-subtractiveintegrated hybrid manufacturing process can be realized.