Investigation On The Microstructure And Mechanical Properties Of Al₂Ti₃V₂ZrB High Entropy Alloy Particle Reinforced Aluminum Matrix Composite

Aiming at the problems existing in the traditional ceramic particle reinforced and and high entropy alloy reinforced aluminum matrix composites,a lightweight Al₂Ti₃V₂Zr B high entropy alloy reinforcements were developed.Al₂Ti₃V₂Zr B/2024composites were fabricated.The effects of processes of ball milling and sintering of Al₂Ti₃V₂Zr B/2024 composites powder and the content of Al₂Ti₃V₂Zr B high entropy alloy reinforcements on the microstructure and properties of Al₂Ti₃V₂Zr B/2024Al composites were investigated in detail.The following experimental results were obtained:The fine high entropy alloy powder with particle size of 2-3mm can be obtainedafter ball milling for 10 hours at the ball milling speed of 350r/min.The Al₂Ti₃V₂Zr B high entropy alloys with the microstructure of BCC matrix and precipitates of HCP phase,?-Ti B₁₂phase and?-Al Zr₃phase can be obtained after the high entropy alloy powder being sintered for 2 hours at 1350 ^oC.The hardness and density of the alloys reached to 5.244 g/cm³and 1153.9 HV respectively.The Al₂Ti₃V₂Zr B particle with a size of 0.5-1?m obtained by mechanical ball milling for48 hours at 350 r/min ball speed is a very competitive alternative reinforcement of aluminum matrix composites.Al₂Ti₃V₂Zr B reinforcement had a good strengthening effect on Al₂Ti₃V₂Zr B/2024Al composites,but the microstructure and mechanical properties of the composites were affected by ball milling process,sintering process and volume fraction of Al₂Ti₃V₂Zr B reinforcement in Al₂Ti₃V₂Zr B/2024Al composites.The sintering temperature affected the size and distribution of Al₂Ti₃V₂Zr B reinforcements in 2024 Al matrix,and thus affected the mechanical properties of Al₂Ti₃V₂Zr B/2024Al composites.The composites fabricated by the optimum sintering process oftemperature and 2 hours sintering time had the most evenly distribution of Al₂Ti₃V₂Zr B reinforcement particle in Al₂Ti₃V₂Zr B/2024Al composites,which resulted in the composites had the highest density and hardness.The ball milling process had a significant effect on the microstructure of Al₂Ti₃V₂Zr B/2024Al composites.Too high ball milling speed or too long ball milling time can cause the agglomeration of Al₂Ti₃V₂Zr B particles and affected the microstructure uniformity of the composites.The composites fabricated by the best ball milling process with a ball milling speed of 150 r/min and a ball milling time of 5hours had the most uniform distribution of Al₂Ti₃V₂Zr B reinforcements in the 2024Al matrix,the highest hardness,compressive strength and the best plasticity.With the increase of the content of Al₂Ti₃V₂Zr B reinforcements,the hardness ofthe composites increased while the compressive strength increased first and then decreased.The reason is that the distribution uniformity of reinforcement particles in Al₂Ti₃V₂Zr B/2024Al composites increased first and then decreased with the increase of volume fraction of Al₂Ti₃V₂Zr B reinforcement,which affected the dispersion strengthening of Al₂Ti₃V₂Zr B reinforcement,load transfer strengthening of interface between Al₂Ti₃V₂Zr B reinforcement and 2024Al matrix and fine grain strengthening effect of 2024 Al matrix.