Study On High-temperature Mechanical Properties And Corrosion Resistance Of (C_f+Ti_p)/6061Al Composites

The objectives of this research are to use liquid infiltration squeeze castingmethod to fabricate Cf/Al and three kinds of (Cf+Tip)/Al composites with differentsizes of Ti particles, to study on the impacts of Ti particles on its high-temperaturemechanical properties and corrosion resistence properties.The microstructure of the composites showed that mechanical bonding betweencarbon firber and aluminum matrix is good, without obvious macroscopic defects.The reaction products at fiber/aluminum interface are mainly Al4C3and Fe-richintermetallic particles. Ti particles are mainly distributed in the Al matrix andseveral Ti-Al intermetallic compounds have been formed.There points bend test at room temperature showed that bending strength of(Cf+Tip)/Al decreased while the size of reinforced Ti particles decreased.Specifically, when the size of the reinforced Ti particle are40μm,3μm,1μm, roomtemperature bending strength of those composites are reduced from677.4MPa to609.0MPa,515.8MPa,473.4MPa, respectively.Bending performance of Cf/Al and (Cf+Tip)/Al at high temperature of100°C to600°C has been evaluated. It showed when temperature lower than300°C, bendingstrength of all composites remains stable. And Cf/Al,(Cf+Tip(40μm))/Al compositesreached its maximum bending strength at400oC, that is800MPa approximately.(Cf+Tip(3μm))/Al and (Cf+Tip(1μm))/Al reached its maximum bending strenght at500oC,that is700MPa approximately. At600°C, after modified with3μm Ti particles,bending strength of Cf/Al has been increased from156.7MPa to511.5MPa.Exploration of heat treatment process showed that optimized heat treatment processof (Cf+Tip(3μm))/Al is550°C/2h. Under this process their bend strength at roomtemperature has been increased from515MPa to635MPa.Immersing corrosion, electrochemical polarization and electrochemicalimpedance spectroscopy have been conducted to explain the corrosion mechanismof Cf/Al. With comprehensive analysis, relative corrosion resistance of thosecomposites is:(Cf+Tip(1μm))/Al>Cf/Al>(Cf+Tip(3μm))/Al>(Cf+Tip(1μm))/Al. Reinforcedwith Ti particles of1μm was not only improved the corrosion potential, reduced theaverage corrosion current density, but also increased the polarization resistance.