Influence Of Alloying And Modification On The Microstructure And Mechanical Properties Of In-Situ TiC_p/Fe Composites

In-situ synthesized TiC particulate reinforced iron composites(TiC_p/Fe composites), because of its favorable microstructure and good combined mechanical properties, are becoming a prospect candidate in more and more wider industrial application fields. But in the in-situ reaction process, large quantities of flake graphite and some Fe₃C always formed from the alloying liquid, which destroyed sharply the integrity and continuity of the matrix and deceased the mechanical properties of TiC_p/Fe composites.For the purpose of reducing the amount of harmfull phase especially the flake graphite, alloying and modification techniques were used to modify the microstructure and to improve mechanical properties of TiC_p/Fe composites. In present work, the influenceof alloying with copper, nickel, tin and modification with SiFe75 on the quality of harmfull phase especially the flake graphite and the microstructure and mechanical properties of TiC_p/Fe composites were investigated.Copper, nickel and tin all have a good effect on reducing the content of flake graphite, modifying the microstructure and increasing the mechanical properties of TiC_p/Fe composites. Copper has a strong effect on decrease the amount of flake graphite in TiC_p/Fe composites, especially when the copper content increased to 1.5%, almost no flake graphite could be observed. Nickel has a much better effect on increasing the impact toughness and tensile strength of TiC_p/Fe composites than copper and tin. Tine has a stronger effect on increasing the hardness of TiC_p/Fe composites than copper and nickel.The microstructure and mechanical properties were improved by adding SiFe75 modification. On the effect of SiFe75 modification flake graphite were translate to subglobular and short bar graphite, which decreased the graphite destroying on the integrity and density of matrix. After the modifying of SiFe75, the microstructure of TiC_p/Fe composites were refined and the content of pearlite matrix also increased. With the modifying of SiFe75, the impact toughness and tensile strength increased which improved the mechanical properties of TiC_p/Fe composites obviously.