Preparation And Damping Properties Of Ti₂AlC/Mg-based Composites With Two-scale Three-dimensional Network

In this paper,AZ91D magnesium alloy was used as the matrix,and a two-scale three-dimensional network Ti₂AlC/Mg matrix composite was prepared by precast magnesium infiltration solution.The preparation process,microstructure,mechanical properties and damping properties of the composites were studied.The mechanism of strengthening and damping is summarized and analyzed.The main research results are as follows:The structure of the two-scale porous three-dimensional network ceramic plate was studied and optimized by theoretical modal analysis.Corresponding prepress and sintering dies were designed and the corresponding prepress molding and sintering process were formed.The magnesium-assisted infiltration process and its related parameters were studied.Finally,two-scale 3 d network Ti₂AlC/Mg matrix composites were prepared.By analyzing the microstructure of Ti₂AlC ceramic plate and composite material,it can be seen that the microstructure of Ti₂AlC ceramic plate is dispersed and connected with sufficient strength,which can be used as the skeleton of magnesium solution infiltration.The microstructure of the composite is uniform,with a few blind holes.The matrix magnesium alloy at each location is surrounded by Ti₂AlC ceramic reinforcing phase and has a good interface.According to the EDS line scanning results at the interface and the selected element analysis,the magnesium solution successfully infiltrated into the extremely fine pores of Ti₂AlC ceramic phase,and no reaction took place at the two-phase interface.Compared with the matrix magnesium alloy,the flexural performance of the composite material has been improved to a certain extent.The magnesium matrix and ceramics provide a good synergy of strength and toughness,but a small number of blind holes affect the further improvement of the mechanical properties of the composite material.Compared with magnesium matrix,composite material has higher storage modulus,and the internal consumption of composite material is the same as that of magnesium alloy matrix in the range of available applications.The main damping mechanism of composites can be attributed to the consumption of strain energy by the interface damping,dislocation damping and the bending band in the Ti₂AlC ceramic phase The micro-model of the composite material was reconstructed and its equivalent modulus was predicted by finite element method.The calculation result was31.25GPa.It is expected that the strength and damping properties of magnesium matrix composites can be further improved by using finite element analysis to further optimize the reinforced structure.The infiltration process of the porosity of three-dimensional porous ceramics and Strength and damping properties of high magnesium matrix composites can be further optimized.