Titanium alloy is an important material in the 21st century and its consumption in the aerospace and energy fields is increasing. In the production and repair of titanium alloy, the problem of energy saving and consumption reduction is becoming increasingly important. Laser-cladding technology with optimized parameters can bring great economic benefit. In order to obtain the best process parameters of laser-cladding TC4 alloy powder, a method of laser-cladding parameters’ optimization based on the RSM and NSGA-II Algorithm is proposed. The BBD (Box–Behnken Design) experiment scheme was designed by the response surface method. A surrogate model between input variables (laser power, scanning speed, and powder-feeding speed) and response values (macroscopic quality, microhardness, and average friction coefficient) was established. The second generation non-dominant sorting genetic algorithm (NSGA-II) was used to optimize the process parameters and the optimization results were verified by experiments. The results show that the optimum parameters are a laser power of 2600 W, scanning speed of 19.1 mm/s, and powder-feeding rate of 12.2 g/min. The samples prepared with the best process parameters show mainly abrasive wear, accompanied by a small amount of adhesive wear. Its wear depth is 7.71 μm and the average friction coefficient is 0.293. After cladding, the macroscopic quality of the cladding layer is increased by 5.8%, the microhardness is increased by 10.1%, and the average friction coefficient is reduced by 27.6%.

Aiming at the difficulty of temperature control in the laser cladding process of high-temperature nickel-based alloys, the influence of cladding parameters on the temperature of the molten pool, and the quality of the cladding layer were explored. Firstly, through the analysis of the finite element method, the Inconel718 single-pass cladding model was established on the surface of 45 steel by using parametric language and life–death element technology, the influence of different laser power and scanning speed on the temperature of the molten pool center was explored, and reasonable process parameters scope were selected. Secondly, taking the cladding parameters as independent variables, and taking the dilution rate and forming coefficient of the cladding layer as the response variables, using BBD (Box–Behnken Design) to design experiments the response surface analysis method was used to establish the regression prediction model of the cladding process parameters and response indicators, and the genetic algorithm was used to carry out multi-objective optimization to obtain the best results. The optimal parameter combination is a laser power of 1756 W, a scanning speed of 19.43 mm/s, and a powder feeding rate of 19.878 g/min. Finally, a multi-pass lap joint experiment was carried out with the optimal parameters, and it was found that the cladding layer has a dense and fine structure and a good metallurgical bond with the matrix, which can effectively guide the actual production.

In recent years, the adhesive technology has been widely used in the production of high-strength joins and precise positioning of various materials, such as metals, glass and composite materials. The adhesive technology has become a promising assembly process in the aerospace field due to its versatility, low creep and high damage tolerance. However, the reliability and predictability of adhesive bonding still require further development due to the complex operating conditions involved. Therefore, this article reviews and discusses the latest advances in aerospace adhesive technology, such as methods for improving bonding performance, bonding techniques (including joints structure and failure modes) and self-healing adhesive layers. Additionally, the current research results are summarised, and possible development trends and research directions in the field of adhesive bonding are prospected.

In the realm of optomechanical joints, the roughness of the component frequently limits the bonded joint's stability and dependability. This study investigates the failure mechanisms and interfacial stress transfer characteristics of bonded structures with six controlled roughness levels to elucidate roughness-dependent adhesion behavior. Shear experiments have been carried out to analyze the failure mechanisms of bonded joints. The results indicate that when roughness increases, shear strength first rises and subsequently falls. When the surface roughness of the duralumin alloy is 4.2 ± 0.75 μm, the shear strength reaches its maximum value of 11.97 MPa. After analyzing the surface characteristics of substrates with various degrees of roughness, the results show that increasing surface roughness can significantly change the substrate's surface energy, wettability, and contact area while also greatly changing the bonding quality. The fractographic evaluation identified interfacial debonding and cohesive-adhesive hybrid failure as the predominant fracture mechanisms. Specimens exhibiting hybrid failure demonstrated enhanced interfacial load transfer capability through synergistic contributions from both adhesive-substrate bonding and bulk adhesive deformation. This research offers an important reference for the manufacture and application of epoxy adhesive and duralumin alloy joints. It has a guiding significance for improving the performance and reliability of joints.