Study On The Al₂O₃ Particles Reinforced Aluminum Matrix Composites

Al₂O₃/Al composite attracts more and more attention in industry because of its high electrical and thermal conductivity, wear-resistance and low thermal expansion coefficient. This paper deals with a new method for Al₂O₃/Al matrix composite preparation, which could be used for producing cylinder liner of high quality, Special equipment with the combination of electromagnetic and mechanical stirring technology under vacuum condition is prepared in the experiment. Composite specimens with Al₂O₃ volume proportion of 5%, 10%, 15%, 20% are made respectively, and after microstructure analysis of the specimens and matrix metal, mechanical property tests, wear-resistance experiments and comparisons with gray cast iron and 45 carbon steel, main conclusions are drawn as follows:(1) Al₂O₃/Al composites have as higher wear resistance properties as one order of magnitude than matrix alloy in lubricated sliding case. Microscopic analysis of the abrasion surface indicates that wear mechanism of composites and matrix alloy includes sticking abrasion and grinding-particle abrasion on the materials.(2) SEM analysis shows that, when the particle volume proportion is over 10%, the particles will be gathered and agglomerated, which means process parameters should be optimized.(3) In a certain range of strengthening particle volume proportion, mechanical properties of Al₂O₃/Al composites increase with the volume proportion of strengthening particles. However, when the volume proportion is excessive, gathering area of strengthening particles and interface between strengthening particles in composites worsens the mechanical property.(4) 10% particle volume proportion makes AAl₂O₃/Al composites of the highest wear-resistance property, which is superior to grey cast iron and 45 carbon steel about the wear-resisting property, but a little inferior about mechanical property. So it could be used as a substitute material for cylinder liner.