| Continuous SiC fiber-reinforced titanium-based composite material(SiC_f/Ti60)has higher specific strength,excellent fatigue resistance and stronger creep resistance than traditional titanium alloys,and uses titanium-based composite materials to prepare structures with a temperature of less than 800?At the same time,the structural design corresponding to it will make the weight reduction effect of the entire structural part as high as 15%-70%,thus greatly improving the thrust-to-weight ratio of the engine.Numerous excellent properties make titanium-based composite materials have broad application prospects in the aerospace industry.In this paper,the SCS-6 SiC_f/Ti60composite ring prepared by the fiber coating method is used as the research object.The process of densification of the SCS-6 SiC_f/Ti60 composite material prepared by the hot isostatic pressing of the fiber coating method by different parameters is simulated by Abaqus finite element analysis software The influence law of thermal residual stress generated in the process.According to the characteristics of the periodicity and symmetry of the fiber,an axisymmetric finite element model is established.The results show that when hot isostatic pressing is used to prepare the SiC_f/Ti60 composite ring,the density and hot isostatic pressing during hot isostatic pressing The relationship of time shows the characteristics of four stages:slow densification stage,accelerated densification stage,rapid densification stage and deceleration densification stage;in the early stage of HIP,the density of the square arrangement is significantly less than that of the hexagonal arrangement;in HIP In the later period,the density increase rate of the square arrangement is significantly higher than that of the hexagonal arrangement,so that the density of the square arrangement and the density of the hexagonal arrangement tend to be the same in the final stage of HIP;if only to achieve full density As a goal,the effect of the two precursor wire stacking arrangements is basically the same;in the early stage of HIP,increasing the volume fraction of SiC fiber can increase the density of the preform,and in the later period of HIP,increasing the volume fraction of SiC fiber can make The compactness of the preform is reduced approximately;increasing the heating rate can significantly shorten the time for the SiC_f/Ti60 composite to fully densify;increasing the pressure increase rate can appropriately increase the SiC_f/Ti60 complex The density of the composite material.In addition,the residual thermal stress of the SiC_f/Ti60 composite was also simulated.The results show that different types of SiC fiber surface coating have a greater impact on the radial thermal residual stress inside the SiC fiber,and the surface coating and Ti60 matrix Radial thermal residual stress has little effect;the type of surface coating has a great influence on the hoop thermal residual stress of the surface coating,and has little influence on the hoop thermal residual stress inside the SiC fiber and Ti60 matrix;from the perspective of stress gradient,Gd surface coating type is the best SiC fiber surface coating;different SiC fiber surface coating thickness has little effect on the radial and hoop thermal residual stress of the composite;as the thickness of the fiber coating increases,The radial and hoop thermal residual stress gradients in the composite also decrease;the higher the SiC fiber volume fraction,the smaller the radial thermal residual compressive stress inside the SiC fiber and Ti60 matrix;for the hoop thermal residual stress,The higher the SiC fiber volume fraction,the smaller the hoop thermal residual compressive stress inside the SiC fiber,and the larger the hoop thermal residual compressive stress inside the Ti60 matrix,and the hoop thermal residual inside the Ti60matrix Stress gradient of the SiC fiber volume fraction negatively correlated!As the volume fraction of SiC fibers increases,the stress gradient in the composite also decreases. |
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