Microchannel heat sinks have features-high heat transfer performance, compact structure, lightweight, easy to integrate packaging and so on, which are ideal to solve the cooling problem of aerospace engine. In this review, the manufacturing methods of microchannels are firstly introduced, and the manufacturing mechanisms and characteristics are analyzed and compared. The applications of microchannel cooling technology in aerospace field are then presented such as the microchannel cooling in the combustion chamber wall, precooler and turbine blade. Finally, the challenges of the microchannel cooling technology in the aerospace field are discussed.

TiAl-base alloys exhibit outstanding balanced mechanical properties at high temperatures, which are considered as important light-weight structural candidates within 650-1000℃ in aerospace industry. The microstructures of TiAl alloys are unstable and decompose at evaluated temperatures, which would affect the mechanical properties. Therefore, the thermal stability and the microstructural evolution and the influence on properties have attracted close attentions for a long time. In this paper, the connotation of thermal stability of TiAl-base alloys is introduced. The microstructures evolution and phase transition of TiAl-base alloys under high temperature conditions are discussed and analyzed, including the discontinuous coarsening of α2/γ lamella and the continuous coarsening of γ lath strip, the decomposition of α2 phase and the change of B2 (ω) phase. The effects of temperature, time, alloying elements and thermal load on microstructures, thermal stability and mechanical properties of TiAl alloy are summarized and summarized. Finally, the research direction of thermal stability of TiAl alloy is summarized and forecasted.

The electric pulse assisted aging process of 2219 aluminum alloy plates is simulated and studied by experiments.The effect of electric pulse on the current density distribution, Joule heat effect, mechanical properties and precipitates microstructure is investigated by simulation analysis, electric pulse assisted aging test, tensile test and transmission electron microscopy observation. The results show that the peak current density of the electric pulse assisted aged plate is symmetrically distributed. Under the current density of 80A/cm2, the peak current density in most areas of the sheet is between 40 and 120A/cm2. Meanwhile, the temperature rise of the plate is less than 1℃ . Compared with the conventional aging process, the aging precipitation process is accelerated and the distribution of precipitates is homogenized after the electric pulse assisted aging process. The peak aging time was shortened from 15h to 10h, peak aging yield strength also increased from 283MPa to 303MPa. Furthermore, it indicated that the electric pulse assisted aging process can shorten the production time and improve the mechanical properties of the studied alloy.

Nickel-base single crystal superalloy is frequently used for the turbine blades of aero-engine. The alloying element segregation during its solidification process leads to the heterogeneity in microstructure, which could be fatal to the high temperature mechanical property. DD5 is one of the second generation of domestic single crystal superalloy. A cylinder specimen was withdrawn by a rate of 3mm/min. Microstructure observation and thermodynamic calculation reveals the cast microstructure includes γ, γ' and carbide. Electron probe microanalysis was employed for the measurement of alloying element segregation across the dendrites and interdendrites, indicating that Re and W tends to segregate into dendrites while Al and Ta concentration is higher in interdendritic regions. In particular, the carbide precipitation in in-terdendritic region is proven to be Ta enriched, which is supposed to be MC type carbide. On this basis, phase field simulation on the microstructure evolution and alloying element segregation during solidification is performed via Mi-cress software. The simulated microstructure is quite similar to the experimental observation, and the alloying element distribution is in accordance with EPMA measurement.

Due to multiple specifications and variety of metallic materials of aviation industry such as steel, aluminum alloy and titanium alloy etc, heat treatment process of metallic materials has high quality requirement and is complex. With increasing attention on heat treatment in aviation manufacture factories, many long existing problems have been resolved gradually. Compared with emphasis on results and qualification rate of heat treatment previously, more importance should be attached to process parameter control and existing data potentiality exploitation. This thesis briefly describes heat treatment of a few types of metallic materials, puts forward some problems and simple analysis, and proposes some improvement suggestions for the reference of related personnel.

Combined with the actual demand, a highly reliable omni-directional wheel and an omni-directional vehicle with advantages of compact, high load-bearing, high positioning accuracy were established. The omni-directional vehicle with four electric omni-directional wheels that moving and turning in one set, that is, moving and rotation of each wheel are driven by two motors respectively. Several main performance indexes of omni-directional vehicle such as omnidirectional move function, carrying capacity, kinematic accuracy and emergency reaction ability were experimented. The experiment results showed that the design and development of omni-directional vehicle has achieved the expected targets, and omni-directional vehicle has fulfilled the task with an industrial robot for flexible assembly successfully.

Shell component like specimens were designed and then produced. One side of surface was shot peening processed by wet blast processed and the back surface was not. Experimental date and analytical results indicated that compressive residual stress exists on the back surface, the amount of residual stress is higher on pure shell specimen than shell structure reinforced by ribs on back surface, tensile stress could be produce by increasing transverse stiffness, residual stress is controlled by parameters of wall thickness and shot peening intensity and it can be decreased by the lower shot peening intensity or increasing the wall thickness. The founding of this research can be helpful in improving shot peening parameter and modifying the topology of components.

There are some phenomena happen for automated fiber placement of sandwich structures, such as the honeycomb is prone to crush due to the compression of head, the bridge at the interface between the honeycomb and the bottom, the head contact with the honeycomb, etc. To solve the above problems, the automated fiber placement for honeycomb structures were investigated, which included the heating parameters and the compression force, the simulation of the placement, the stage of the honeycomb core, and the limit angle of the honeycomb, etc. The fiber placement path of sandwich structures were designed and the sandwich structures were manufactured, meanwhile the defects during the process were classified and analyzed, and solved experimentally. The investigation shows that the heating parameter would affect the layup ability of the prepreg, overheating can burn the prepreg. To assure the layup quality, the angle of the honeycomb is better to be less than 30 degree, and the honeycomb has a smooth connection with the bottom, the last but not the least, the size and the position of the honeycomb is crucial for the process quality.

In order to insure the influence of crimping dimension on the locking properties of titanium alloy selflocking nut, the locking properties at different crimping dimension were detected by the machine in this paper, and the regularity between crimping dimension and locking properties was gained simultaneously. The results show that the selflocking torque and breakaway torque increase at beginning and then decrease with the increasing of frequency. The variant region was smaller at the 0.05mm and 0.10mm crimping dimension, and that at 0.15mm crimping dimension was biggest. The linear relationship appears between seating torque and preload, and the smaller crimping dimension is, the bigger slope of the linear is. The wrenching-stretching coefficient is 0.09, 0.12 and 0.16 at the crimping dimension of 0.05mm, 0.10mm and 0.15mm, respectively.

Considering the features of wedge structure on the trailing edge of aircraft wing surface during the assembly riveting, the rivets must be selected in appropriate length according to the accurate measurement of edge angle and laminated thickness of pin hole, so as to realize the double face riveting. This paper designs a special compound measure based on the requirement that wedge angle and laminated thickness of pin hole must be measured accurately by one time only, Therefore, the measurement requirements to wedge structure on the trailing edge of aircraft wing surface could be satisfied completely through the design in measure structure and the analysis on potential error.

With the extensive use of composite and titanium material in present-day aircraft structure and higher requirement of drilling efficiency and drilling quality, the drilling technology improves correspondingly. For development and application of drilling technology, this article describes the process characteristics, the main tools and the application scope.

The drilling and riveting process is widely used in the assembly of carrier rocket, which makes the efficiency and quality of drilling become the important factor affecting the assembly process. According to the problem existing in the drilling of thick laminated plate (thickness larger than 10mm) of carrier rocket, such as drill break, large noise and burr etc, experiment study of the influence of cooling conditions on the drilling were carried out. The cutting force was measured by a piezoelectric dynamometer, the aperture was measured with an outline projector and the burr was observed and measured by a digital stereo microscope. Through the measurement of contour projector and depth of field stereo microscope, the effects of three cooling conditions, including no cooling, air cooling and liquid nitrogen cooling, on the drilling were analyzed from the aspects of drilling force, diameter and burr. The results show that the largest number of hole can be obtained under the condition of air cooling. The cutting force is the largest under the condition of no cooling and that is smallest under the condition of liquid nitrogen cooling. The suddenly fracture of drill is due to the adhesions of chip under the high temperature because there is no obvious tool wear before the drill fracture.

The paper introduces the process optimization method of TA2 components, such as increasing finishing proess, strengthening the liquid control, improving welding argon gas protection, to minimize the chance of TA2 fine powder adhering to the wall. The experiment reaches the expected effect and reduces the cost. It mainly introduces the TA2 cleaning technology of the tee through, right through with large length to diameter ratio of the high cleanliness requirements pressuring piping, provids a new method for tailings sensitive parts cleaning, and the result is highly transformed with innovation. The paper developes the TA2 detecting method of the tee through, right through of the high cleanliness requirements pressuring piping, provides the fine powder of quantitative tools, and the military, social benefits. This method has been tested by different products with stable and reliable performance.

Polycrystalline diamond (PCD) end mill was applied during the trimming experiment of CFRP by introducing the definition of workpiece inclined angle. The milling forces were recoded and different types of machining defects were observed at the same time. The influences of carbon fiber angle, workpiece inclined angle and feed rate on the types and evolution of machining defects were analyzed. The results show that the main machining defect is avulsion of carbon fiber bundles with small amount of chipping, burrs and delamination. The feed rate of cutter is the most significant factor on the occurrence of machining defects especially on the avulsion of fiber bundles. The cutting force perpendicular to the laminate panel has the direct influence on the occurrence and evolution of defects.