Titanium alloy is widely used in aerospace parts due to its high specific strength and low density. However, titanium alloys also have weaknesses such as low hardness, poor wear resistance, and poor high-temperature oxidation resistance. Fatigue problems caused by surface stress concentration sensitivity are also prominent. Surface engineering technology needs to be applied to overcome the three major problems of wear, corrosion and fatigue. Here, this article introduces the research progress of wear-resistant coating, anti-oxidation coating and anti-fatigue surface modification technology of titanium alloy in the past ten years, and looks forward to the development trend of technologies, to provide reference for scientific and engineering researches of surface engineering technology.

Abrasive belt abrasive wear will affect the surface quality of the grinding, and then affect the service performance of the grinding components. This paper uses the surface integrity as the evaluation index to evaluate the grinding quality of the abrasive belt before and after abrasive wear, and analyzes the effect of abrasive wear on the surface roughness, residual stress and surface micro-hardness of the abrasive belt grinding TC17. Results show that: after the abrasive grains are worn, due to the uniformity of the abrasive grains, more abrasive grains per unit area actually involved in cutting, grinding depth reduced. The grinding texture is uniform and fine, and the roughness decreases up to 70.3%. Compared with worn abrasive grains, the machined surface of sharp abrasive belts has undergone significant plastic deformation, and the hardness of abrasive abrasive belt surface can be increased to more than 20% by work hardening. On the other hand, the material plastic flow occurs on the surface processed by wore abrasive belt, so the surface micro-hardness is slightly lower than the matrix hardness. In this experiment, grinding surface has realized the transformation of residual tensile stress (about 400MPa) to residual compressive stress (about –300MPa). The abrasive wear of different abrasive belts has different effects on surface residual stress. Abrasive wear of zirconium corundum abrasive belt increases surface residual compressive stress by 33%, and abrasive wear of diamond abrasive belt reduces surface residual compressive stress by 34%.

As a critical material for high-end equipment parts like aero-engines, titanium alloy has good high specific strength, excellent corrosion resistance and super fracture toughness and fatigue performance. As a typical aerospace difficult-to-machine material, the surface integrity of the titanium alloy during the manufacturing process has a crucial impact on its service performance and reliability. On this basis, the research advances on the current research of surface integrity in the titanium alloy manufacturing process are reviewed from the four technological perspectives of cutting, grinding, composite processing and non-traditional machining. Finally, the prospect of future research on cutting, grinding, composite processing and non-traditional machining technology of titanium alloy are prospected.

Titanium alloy material of aero-engine blade is prone to burn and adhesion in CNC grinding and polishing. In this paper, the CNC polishing experiment of titanium TC4 using flexible polishing wheel with superhard abrasive is carried out. The effects of polishing speed, feed speed, compression and row pitch on polishing removal depth and surface roughness are studied and analyzed. And primary and secondary relationship of polishing parameters are explored by the orthogonal tests. Finally, the selection strategy of process parameters for polishing TC4 is given, which can provide a theoretical and technical basis for TC4 polishing of aero-engine blade and blisk using flexible polishing wheel with superhard abrasive.

To study the impact of TC6 titanium alloy laser shocking peening (LSP) treatment on the vibration fatigue life, different shocking peening times were used to laser peening TC6 titanium alloy, and the vibration fatigue test system was used to test vibration fatigue on the samples. X-ray diffractometer and microhardness tester are used to test the residual stress and hardness of the samples before and after LSP, and to study the influence of LSP on the vibration fatigue performance of TC6 titanium alloy. The changes of microstructure after LSP was observed by transmission electron microscope (TEM), and finally observing the vibration fatigue fracture surface of the sample with scanning electron microscope (SEM) to study the influence of LSP on the vibration fatigue fracture surface of TC6 titanium alloy. The results show that the TC6 titanium alloy undergoes strong plastic deformation after laser shot peening, resulting in a large number of dislocations, which can inhibit the initiation and propagation of fatigue cracks in the TC6 titanium alloy sample, and improve the performance mechanical properties of material, thereby effectively improving the vibration fatigue life of TC6 titanium alloy samples.

Superplasticity of TiB_w /TA15 composite sheet under the conditions of 900–960℃ and 5×10^–4~10^–2 s^–1 was studied. The results showed the flow stress of TiB_w /TA15 composite decreases with the deformation temperature increasing and strain rate decreasing, and the strain softening characteristics are significant under the condition of low temperature and high strain. The maximum elongation obtained at 940℃ and 5×10^–3s^–1 was 439%. A constitutive equation based on the Zener–Hollomn parameter and Arrhenius equation was ε·=3.55×10⁸ [sinh（2.0×10^–2 σ）]^1.99 × exp（–6.381×10⁵ /RT） for TiB_w /TA15 composite，and the deformation energy Q=638.1kJ/mol. The superplastic deformation structure of composite materials is closely related to the tensile temperature and strain rate. The high temperature and low strain rate are beneficial to the dynamic recrystallization of the matrix α phase and the healing of the whiskers and the holes in the matrix. The change of grain size contributes more to superplasticity than the effect of voids on superplastic elongation. The low temperature and high strain rate are beneficial to the holes healing at the end of the interface between reinforced phase and matrix. Dynamic recrystallization plays a key role in superplasticity of composites.

In view of the problems of low material removal rate and poor hole diameter uniformity in the honing process, the material removal rate of 9Cr18 stainless steel during the honing process was analyzed, and a set of material removal volume theoretical formulas suitable for honing process were proposed. At the same time, in order to make the hole diameters at different axial positions of the honing hole closer to the same, it is necessary to increase the residence time at the upper and lower overruns to improve the original model. Single-factor honing tests were carried out based on the original model and the optimized model. The single-factor test results showed that, reciprocating speed and honing pressure are significant factors that affect the removal volume of honing materials. Aiming at the difference between the removal volume of the honing material and the hole diameter after honing, the prediction results of the optimized model and the initial model are respectively compared with the corresponding test results, it can be found that the prediction accuracy of the optimized model is increased by 25%–30% compared with the initial model. Adding the resident time in the overtravel section will not reduce the processing efficiency, can improve the dimensional accuracy of the hole after honing, and realize the accurate prediction of the material removal volume.

Laminated shim stock, also known as peelable shims, is made of multi-layer sheet materials. Laminated shim stock is often used to adjust the assembly clearance and plays an important role in the aircraft manufacturing process. The existing manufacturing methods of the laminated shim stock is mainly mechanical milling and conventional blanking, both of which might have delamination phenomenon. In this research, the delamination on the sheared edge in the conventional blanking process of the laminated shim stock is studied. A conventional blanking finite element model of the laminated shim stock is established as well, the Cockroft-Latham damage model is used to analyze damage in the blanking process. It is found from the results of simulation and experiment that the various material behaviors of cross section is the main cause of delamination on the sheared edge.

Microstructure characterization and reconstruction (MCR) can be used to establish the processing–structure-–property (PSP) relationship, which has become the focus of computational materials science and material design. In this paper, threshold segmentation is used to identify the metallographic photos of heterogeneous materials as textures composed of different phases, combined with multi-resolution Gaussian pyramids for reconstruction. The reconstruction results after particle number supplement are iteratively optimized with percentage of each phase as target parameter. Thereby, this paper proposes an innovative MCR texture synthesis algorithm with controllable area fraction, which is used to reconstruct the microstructure of heterogeneous AlSi–PHB seal coating. Two-point correlation functions of PHB phase and pore are utilized to confirm the effectiveness of the proposed algorithm. On this basis, two sets of metallographic photos are used to reconstruct 20 sets of models, and the maximum error of the two-point correlation function of the reconstructed results is 8.8×10^–5 . This paper provides a solution for the accurate reconstruction of heterogeneous materials.

In this study, the numerical simulation of the curing deformation of a co-cured stiffened composite panel is implemented. The curing deformation predictions of the T800 carbon fiber/epoxy resin composite stiffened panel are in good agreement with the experimental test results, which show the predictive capacity of the proposed simulation method. Through the simulation, the influences of curing parameters including heating/cooling rate, holding time and structural size parameters including width and height of stiffener and fillet radius on the curing deformation of the stiffened panel are further analyzed. These results are expected to provide guidance for the curing deformation control of co-cured stiffened composite panels from the perspective of process design and structural design.

In the manufacturing process of electron beam freeform fabrication, the temperature distribution of the part can be improved by scanning the forming area of the part with electron beam and controlling the heat input, and the annealing along the part can be realized to reduce the stress and control the deformation. The high-speed scanning system of electron beam is built by using industrial computer, waveform generator, scanning coil and its driving circuit, and dynamic focusing coil and its driving circuit. The functions of high-speed scanning and dynamic focusing of electron beam are realized. Based on LabVIEW, the control system of real time annealing scanning is developed, and the control method based on pixel lattice positioning and dynamic aggregation is proposed to realize the precise positioning and heat input control of electron beam scanning; The influence of different scanning paths on the temperature uniformity of the heat source is studied, and the temperature of the scanning area is measured by using multi-point synchronous temperature measurement circuit. The experimental results show that the scanning position and heat input can be accurately controlled by the electron beam real time annealing system, and the uniformity of the temperature distribution of the surface heat source can be significantly improved by optimizing the scanning path.