Study On Preparation Of Ti₃SiC₂ Ceramic Reinforced Al Matrix Composites And Its Performance

Ti₃SiC₂ has been applied in many fields such as conductive anti-friction materials,biomedical materials and damping materials due to its excellent electrical and thermal conductivity,thermal stability and self-lubricating.In this paper,Ti₃SiC₂ reinforced Al matrix composites with excellent performance were fabricated by combination of Ti₃SiC₂ ceramic and Al alloy.Porous Ti₃SiC₂ with different porosities were prepared by pressureless sintering with pore-forming agent and spark plasma sintering?SPS?.Two kinds of particle reinforced Al matrix composites,namely Al/Ti₃SiC₂ and Al-Si/Ti₃SiC₂,were prepared by SPS.Three-dimensional Ti₃SiC₂ reinforced Al matrix composites were prepared by pressureless infiltration with melt-spun 6061 aluminum alloy ribbons and porous Ti₃SiC₂.The phase constitution,microstructures,thermal expansion and mechanical properties of Ti₃SiC₂ and Ti₃SiC₂ reinforced Al matrix composites were analyzed by XRD,SEM,three-point bending,compression and thermal dilatometer.The dry friction and wear properties of Al/Ti₃SiC₂ composites were also investigated.?1?Porous Ti₃SiC₂ with controlled pore structure were prepared by different pore-forming agents.Porous Ti₃SiC₂ preform was prepared by NaCl pore-forming agent and elemental powders Ti,Si and graphite.The highest overall porosity,open porosity and relative open porosity of porous Ti₃SiC₂ was 75 %,73 % and 96 %,respectively.However,a small amount of impurities such as TiC,TiSi2 and Ti5Si3 were detected.The highest content of Ti₃SiC₂ could reach to 97.8 %.The highest compressive strength was 58 MPa.The highest overall porosity,open porosity and relative open porosity of Ti₃SiC₂ preforms prepared by NH4HCO3 pore-forming agent and Ti₃SiC₂ powders was 59.2 %,53.2 % and 91 %,respectively.The highest compressive strength reached to 107 MPa.The porosity of Ti₃SiC₂ preforms prepared by SPS was ranged from 0.7 % to 16.2 %.The compressive strength reached to 685 MPa.Decomposition of Ti₃SiC₂ was hardly detected.?2?Al/Ti₃SiC₂ and Al-Si/Ti₃SiC₂ composites were prepared by SPS.The hardness of the composites increased with the increasing Ti₃SiC₂ content.The highest relative density,hardness,three-point bending and compressive strength of Al/Ti₃SiC₂ composites was 93.4 %,196 HV,385 MPa and 395 MPa,respectively.When Ti₃SiC₂ content of the composites was 10 wt.%,the failure behavior of Al/Ti₃SiC₂ composite was plastic.When the addition amount of Ti₃SiC₂ reached to 25 wt.%,the failure behavior of Al/Ti₃SiC₂ composite was brittle.The thermal expansion coefficient of the composites was 1.94×10-5 /K?250 °C?and decreased with the increasing Ti₃SiC₂ content.The highest density,hardness,three-point bending and compressive strength of Al-Si/Ti₃SiC₂ composites was 96.7 %,218 HV,260 MPa and 563 MPa,respectively.However,the three-point bending decreased with the increasing Ti₃SiC₂ content.The failure behavior of Al-Si/Ti₃SiC₂ composite was brittle.The thermal expansion coefficient of the composites was 1.8×10-5 /K?250 °C?.?3?Three-dimensional Ti₃SiC₂ reinforced Al matrix composites with the density ranged from 3.04 to 3.87 g/cm3 were prepared by melt infiltration with melt-spun AA6061 alloy under 950 °C.Impurities such as Si,Al2O3 and Al8SiC7 produced during infiltrating,which had a positive effect on the mechanical property.The highest hardness and compressive strength of the composites was 749 HV and 932 MPa,respectively.?4?The friction coefficient and worn rate of Al/Ti₃SiC₂ and Al-Si/Ti₃SiC₂ decreased with the increase of Ti₃SiC₂ content under different loads.The lowest friction coefficient and worn rate of Al/Ti₃SiC₂ composites was 0.195 and 3.44×10-4 mm3/Nm,respectively.The lowest friction coefficient and worn rate of Al-Si/Ti₃SiC₂ composites was 0.311 and 1.3×10-4 mm3/Nm,respectively.The worn rate of three-dimensional Ti₃SiC₂ reinforced Al matrix composites was 7.21×10-5 mm3/Nm.The abrasive resistance of three-dimensional Ti₃SiC₂ reinforced Al matrix composites was better than the one of Ti₃SiC₂ particle reinforced Al matrix composites.