Preparation Of Large Particles Of Corundum/Metal Wear-resistant Composites And Numerical Simulation

At present, the research of corundum particles/iron matrix composites mainly involves the corundum of the particle size less than3mm. Study of large particles of corundum/iron matrix composites has rarely been reported. In the field of metallurgy and conveyance of mining, large particles of corundum in the iron matrix to form the composites might replace ceramic-metal with organic glue, because it has excellent anti-wear properties and practicality. This paper mainly studied the fabrication process and performance iron composites containing large particles of corundum.In order to improve the wettability between corundum and iron liquid, this work used Fe2O3to modify corundum. The Fe2O3modification mechanism, fabrication conditions and anti-wear properties of obtained corundum/iron matrix composites were studied. This finite element analysis was used to simulate mechanical properties of the composites. The results showed that:(1) Making use of Fe2O3in the modification experiment, the depth of modified layer on corundum particles increases with increasing temperature, time and porosity of the corundum particles. The depth first increases and then decreases with increasing carbon content. Under conditions of carbon content of3%,1200℃and60min, the modified layer is uniform and over0.2mm in depth. And presence of the interface between corundum and iron indicate the good bonding between them.(2) In corundum/iron composites fabricated by sand casting process, corundum particles combined with the iron well in the top surface, while quite poor in the bottom.(3) Taking advantage of vacuum casting process, we successfully fabricated corundum/iron composites when casting temperature was1500℃. Annealing treatment of composites is at550℃to600℃, and its microstructure is typical cast organization with ferrite and flake graphite. According to the anti-wearing tests, loss of composites is4to6times as low as those of gray cast iron.(4) Making use of finite element analysis, during the fabrication of the composites, composites is easy to produce large casting thermal stress. Simulated bending and compression properties of composites are better than those of cast iron samples. According to the simulation on the tensile experiment, phase of corundum changes internal stress distribution of cast iron samples. The maximum tensile stress appears in the phase of corundum in the composite. The safety factor of composites is higher than cast iron samples.