Preparation Of Three-dimensional Network Ti₂AlC/AZ91D Composite Material By Precursor Method And Its Damping Performance

At present,weapons and equipment,aircraft and high-speed trains are all developing in the direction of light weight,high speed and high power,and their vibration and noise problems are increasingly prominent.Magnesium-based damping composite materials have received extensive attention because of their low density,good mechanical properties,and excellent damping properties.In this paper,the three-dimensional network Ti₂AlC/AZ91D composite material is prepared by using the AZ91D alloy as the matrix and the MAX phase Ti₂AlC as the reinforcing phase,using the precursor method and the melt infiltration method.Were studied.The main findings are as follows:Add 10%?ceramic powder?of Ti powder as a sintering aid to prepare ceramic slurry,dry it through multiple slurry drying,and pressurize sintering under argon atmosphere to obtain porous ceramic prefabricated with three-dimensional network structure The auxiliary pressure infiltration process can be used to prepare a densely organized three-dimensional network of interpenetrating Ti₂AlC/Mg-based composite materials.By observing the microstructure of the ceramic preform,it is found that there are large and small pores with large and small pore sizes distributed in the preform skeleton.The hole structure provides a good structural basis for the subsequent melt infiltration.Through XRD analysis,it is found that the composite material is mainly composed of AZ91D phase and Ti₂AlC phase,Ti C exists as a small amount of second phase,and Al₂O₃ exists as a trace impurity phase.Three-point bending performance test was conducted on the composite material,and the bending strength of the composite material was measured to be 215±17MPa,which was about18%higher than that of the AZ91D magnesium alloy matrix.The introduction of the reinforced phase Ti₂AlC can not only increase the hardness of the AZ91D alloy,but also increase its bending strength.Ti₂AlC particles can readjust the local stress field during the crack growth process through the deformation behaviors of peeling and twisting deformation,delamination cracking and intergranular tearing,thereby consuming part of the energy of crack growth,resisting deformation,and playing the role of toughening.The test result of the loss tangent of the damping performance of the composite material shows that the change trend of the temperature and loss tangent tan?curve of the composite material is similar to that of the AZ91D alloy tan?curve.When the temperature is lower than100?,the loss tangent of the composite material sample tan?increases slowly with the increase of temperature,reaches the highest around 100?,and then the loss tangent decreases with the increase of temperature for a period of time,until It drops to the lowest point around 150?.When the temperature is higher than 150?,the composite material loss tangent tan?increases rapidly with the increase of temperature,and reaches the highest value around 300?,the highest damping peak appears.The damping mechanism of the composite material is different from that of the matrix alloy.The composite material prepared by the precursor method combined with pressure infiltration has the best damping ability,and also has a higher storage modulus,especially under the test condition of 10 Hz,it exhibits more outstanding damping-strength Comprehensive performance.