Study On Microstructures And Properties Of Spinning For Silicon Carbide Particle Reinforced Aluminum Composite

Particulate reinforced aluminum matrix composites?PRAMCs?have excellent comprehensive properties,spinning process in the preparation of large-size thin-walled pipe has a unique advantage.In recent years,it has been studying spinning process technics and manufacturing aviation,aerospace pipe in foreign countries.However domestic relative research is rare reported,which limits the PRAMCs spinning process in China's aerospace applications.In this paper,the key component of a core product in the aerospace field is studied.The purpose of this paper is to study the preparation of large-sized thin-walled aluminum-based composite pipe.Through the research of spinning process and microstructure,exploring the feasibility of the preparation for composite pipe and then providing technical and theoretical support for its preparation.Based on the research by our group and the finite element simulation results of the spinning process,the multi-pass hot spinning experiment of 15%SiCp/2009Al composites was carried out by using the appropriate process parameters.The microstructures,interfaces,precipitates and their properties of the tube,which were in the states of spinning,spinning and solution heat treatment were analyzed and discussed.The main conclusions are as follows:?1?It is possible to prepare spinning pipe with good shape and smooth surface by taking use of the spinning process of this paper.During the strong spinning process,the force of the rotary wheel to the pipe causes the billet to produce two-way deformation,and the axial and tangential grains are obviously elongated and the flow line is formed.The microstructure of the tube is small and the particles are dispersed uniformly.After the deformation of spinning,the particles are broken and distributed along the grain boundary.A suitable spinning process does not result in an increase number of holes in the tissue,but the process selection is inappropriate or too much defects in the tube will lead to cracking of the material.The cracking mechanism of power spinning process is mainly broken particles and matrix ductility damage,as well as a small part of the interface debonding.?2?There are mainly Al,SiC,CuAl₂ and Mg₂Si phases in the tube,and the spinning deformation does not change the phase composition of the composites,but the SiC distribution can be more uniform and the oxide film on the surface of the aluminum particles is broken,as a result that the oxygen element will cluster at the interface.After solution heat treatment,CuAl₂ and Mg₂Si dissolved,Cu evenly distributed in the matrix,but a small amount of Mg is still segregation in the grain boundary and SiC and aluminum matrix interface.?3?The solution heat treatment after spinning can greatly improve the yield strength and tensile strength of SiC/Al composites with a slight decrease in plasticity.The fracture analysis shows that the fracture pattern is mainly composed of mixed fracture,spinning and spinning and solution treatment have more obvious brittle fracture characteristics.?4?In this paper,not only the smaller diameter,thin wall composite material pipe can be formed by spinning process,but also when the tube diameter becomes larger,the wall becomes thicker,the spinning process is still applicable.