Low plasticity burnishing can effectively enhance the fatigue performance, corrosion resistance and damage tolerance property of materials. And it has been widely used abroad in surface modification of aero-engine industry. The basic principle and advantages of the emerging low plasticity burnishing are introduced in this paper. The effects of low plasticity burnishing on surface integrity, such as residual stress, surface roughness, microhardness and microstructure, are summarized. The detailed influences of different processing parameters on surface integrity factors are also analyzed, such as ball diameter, pressure, burnishing speed and number of passes. Finally, the research and development of low plasticity burnishing in China are prospected.

    With the development trend of intelligent manufacturing, the production process of products is becoming more and more flexible. Human-robot collaboration with high flexibility and automation level has become a research hotspot of manufacturing industry. In product assembly, the assembly operation with high flexibility and complex operation still needs to be finished by human, while the robot has the advantages of good repeatability, high load and high accuracy. In time and/or space sharing environment, robots are used to assist workers in assembly, which will reduce ergonomic pressure and workload, and achieve complementary advantages. Based on these understandings, this paper summarizes the research of human-robot collaborative assembly with time-space sharing. This paper reviews the current research status of the four hot spots developed around by scholars in recent years, namely, task allocation for human-robot collaboration, intention recognition for human-robot collaboration, path planning for human-robot collaboration, and safety design for human-robot collaboration collaborative assembly system. The development trend of these four aspects is discussed and prospected.

    Electron beam welding simulation and joint properties of TC4 titanium alloy and T2 copper were studied. By adopting the welding method of multiple offsets which means welding is carried out on copper first and then on titanium side, and the two welds are close but not connected, the tensile strength of Ti/Cu joints can be greatly improved. In order to explore the thermodynamic behavior of the joints, the finite element method (FEM) was used to analyze the temperature field, deformation and stress distribution, then the strengthening mechanism is discussed in combination with microstructure evolution and mechanical properties. Welding on titanium side can remelt the heterogeneous interface formed by welding on copper side, and improve its stress concentration. The tensile fracture shows that it is brittle cleavage fracture, the phase composition on the fracture surface changes from TiCu to Ti₂Cu, and the brittleness decreases.

    With the help of Comsol software, the distribution of magnetic field intensity and flow field inside and outside the focusing tube was simulated. The distribution law of magnetic field intensity was analyzed as well as the mechanism of magnetic field acting on water jet, and the optimum magnetic field intensity was obtained to achieve the best focusing effect of water jet. The results indicate that the best focusing effect of water jet was obtained with the current of 2.2A. The difference of flow field outside the nozzle was observed and analyzed before and after the magnetic field was applied, the vibration and dynamic signal acquire analysis system (CRAS) was used to measure the actual impact force of water jet. The experiment results show that with the magnetic field applied, the effective diameter of abrasive water jet decreases, the focusing effect increases obviously, the original water mist disappears, and the impact force of abrasive water jet increases with the increase of current intensity.

    Carbon fiber reinforced polymer (CFRP) is widely used in aerospace and automotive lightweight manufacturing due to its lightweight, high strength and corrosion resistance. However, there are still some problems in the processing of CFRP, such as edge burrs, interlaminar tearing and so on. Many new processing schemes for CFRP materials are proposed in the industry. As an important processing method, the laser processing has become one of the research hotspots. The hole cutting process of carbon fiber composite plate was studied by using 532nm picosecond laser. The effects of laser rotary cutting, parallel filling cutting and cross filling cutting on machining quality were compared. The quality of the hole and the range of heat affected zone were observed by the confocal microscope. The experimental results showed that the scanning method of laser rotary cutting has the highest removal efficiency, the smallest tapers, and the hot affected zone was small. At the same time, D5766 open-hole tensile standard was adopted to conduct tensile experiments on three kinds of laser scanning hole making samples and mechanical hole making sample, and the results were analyzed. This research would provide new research ideas for high quality processing of CFRP.

    The stainless steel/high strength steel dissimilar metals component was fabricated by plasma arc additive manufacturing with no defects such as pore, non-fusion and slag inclusion and so on. The stereo microscope, metallographic microscope and scanning electron microscope were carried out to study the microstructure of the interface between stainless steel and high strength steel. The results show that the transition zone with a width of 1.1mm will be found when high strength steel is deposited on stainless steel, but no obvious transition zone will be observed when stainless steel is deposited on high strength steel. There are three kinds of interfaces between stainless steel and high strength steel. Type I interface is composed of stainless steel, high strength steel and fusion boundary. The fusion boundary of type II interface is not obvious and high strength steel and stainless steel is separated by martensite. Type II interface is not obvious and is separated by martensite between high strength steel and stainless steel. The transition zone, stainless steel and a region composed of austenitic and ferrite are defined as type III interface. EDS results show that a sharp concentration change of  Cr and Ni exists in the type I interface region, but the concentrations change slowly in the type II interface region and type III interface within a distance of about 70μm and 40μm respectively. The microhardness of the interface area was tested, and its results show that the abrupt hardness width and the component change width had the same trend. From large to small, the order was type II interface > type III interface > type I interface.

    Titanium alloy was known as the intelligent metal in the 21 century. Because of its excellent properties, it played a key role in the welding of high temperature, high strength structure and special joints. As one of the mainstream technologies in the manufacture of high-end equipment, a great deal of attention is being paid today to its advanced welding technology. In this paper, the related properties and main application fields of titanium alloy were briefly introduced. Aiming at the three advanced welding technologies, such as laser welding, electron beam welding and linear friction welding, a review of forming process optimization, defect control, organization evolution rules and mechanical properties analysis were carried out.

    Hole is widely considered as a kind of geometrical–discontinuous structure with high stress or strain concentration.The effect of direct hole cold expansion (HCE) using the mandrel on the fatigue behaviour of centre holes of FGH95 superalloy was investigated. The fatigue fracture and the main parameters of surface integrity of hole wall were characterized by scanning electron microscopy (SEM), roughmeter, X–ray diffraction (XRD) instrument and microhardness tester. The mechanism of the HCE on the fatigue life was also investigated. The results show that the median fatigue life of the HCE specimens increased by above 0.9 times and 10.3 times under room temperature/650MPa and 527℃/575MPa conditions compared to the specimen without HCE, respectively. It is found that the roughnesss of hole wall decreased sharply, while the deep surface strengthened layer with high hardness and residual compressive stress were formed around the hole after HCE. These changes are of great benefit to the enhancement of the fatigue life under room and high temperature. In addition, the exit of grain boundary and the difference of crystallographic orientation of neighbor grains have an evident effect on the fatigue crack growth path.

    With the rapid development of advanced aircraft manufacturing technology, higher requirements are put forward for the design and manufacturing of aircraft structural parts. In order to meet the needs of flexible and automated manufacturing of structural parts in aircraft manufacturing industry, foreign advanced aviation manufacturing enterprises have started the production mode of aircraft structural parts represented by automated production lines. Therefore, this paper summarizes the processing mode of the three-coordinate production line of small and medium-sized aircraft structural parts, and studies the key technologies of the production line for aircraft structural parts processing technology, numerical control programming and measurement etc, which will be applied in the processing of typical structural parts, aiming to verify the feasibility of the key technologies, improve the production efficiency and product quality of aviation manufacturing enterprises, reduce the waste of resources and save costs. Then finally realizing the manufacturing mode of aircraft structural parts production line and playing an important role in improving the overall level of aviation manufacturing technology.

    As a new self-healing agent, Ti₃SiC₂ was added into yttria-stabilized zirconia (YSZ) thermal barrier coatings. By atmospheric plasma spraying (APS), thick coatings were prepared using an YSZ–Ti₃SiC₂ mixing powder. To observe oxidation and self-healing behavior, cracks were prefabricated on the surface of YSZ–Ti₃SiC₂ coating by uniform external load. The prepared samples were then isothermally treated at 1050℃ in air. The phase and morphology evolution of the coatings, as well as the self-healing behavior were investigated via several analyzing methods. The results showed that a part of Ti₃SiC₂ was decomposed into amorphous SiO₂ and TiC after spraying and a double layered structure composed of a TiO₂ outer layer and a TiO₂+SiO₂ inner layer was formed after isothermal treatment. In the process of self-healing, oxidation of the healing agent in the coating led to the growth of silicon oxide and titanium oxide in the cracks. These oxides gradually filled the cracks due to the diffusion-controlled oxidation. Meanwhile, the compressive stress induced by the volume expansion due to SiO₂ and TiO₂ growth in the crack enhanced the healing effect. Eventually the prefabricated cracks were healed.

    The finite element analysis is a numerical method for solving mathematics and physics problems, which is very effective to analysis complex structures or multi-degree of freedom system. To solve the problem of cantilever beam in electrochemical machining (ECM) device for closed integral structure, two devices were designed and finite element analysis was done based on UG. The result shows the strength and stiffness of device B both better than device A, which offered the gist for choosing device. Finally, it is effective for shortening the development cycle to apply parameterized modeling and finite element analysis in ECM device for products.