Research Of Fabrication And Properties For In Situ TiCp/Fe Composite Materials

The preparation of particle reinforced metal matrix composites used by the method of in situ has become one of interesting topics in the field of metal matrix composite materials. The method of in situ accounting to the principle of thermodynamic equilibrium forms reinforcements in the matrix directly, and usually reinforcement is particle or piece. It resolves the problems that wettability is difficult and interface reaction is bad between reinforcements and matrix successfully, which often occurs the method of manual composite. But the study of this technique is concentrated on light metal and its alloy, such as aluminum, nickel etc., and it is very lack in the study of ferrous metal matrix at home and abroad. Whereas this reason, this paper adopts the method which spontaneously forms titanium carbide particles in liquid alloy and studies the fabrication and its properties of TiCp/Fe composite materials by means of the principle of in situ.This technique has two prominent problems: titanium's burning loss and high temperature melt treatment (up 1873K). The author puts forward melting protective cover used by plant ash which can insulate air and enhance effect of heat preservation effectively. At the same time, the author chooses alkalinous magnesite (MgO) for furnace lining which can avoid redox reaction between silicon oxide (SiO2) and titanium, improve fireproofness of furnace lining and decrease titanium's burning loss ratio.The analyses of thermodynamics indicates that it is feasible for the combination reaction of titanium carbide as melting condition. The author optimizes the content of TiCp/Fe composite materials by means of orthogonal design and acquires the best content (%wt):C1.4, Ti2.3, Mn0.5, Si0.6. By wayof analysis for the sample of composite materials, TiC is found that it takes on cube and the interface between matrix and particle is well. The author considers that growth mechanism of TiC particle is the common control of merging growth mechanism as liquid phase and diffusing growth mechanism as solid phase. The mechanical properties of TiCp/Fe composite materials are influenced by size, numbers per area and distribution of reinforcement TiC particle. At the same time, the master factor of failure of composite materials is matrix structure, and primary failure mode is {100} cleavage fracture, so refined grain can enhance impact toughness effectively.The result of research of in situ TiCp/Fe composite materials for impact-abrasive wear resistance indicates that: it is endued with perfect impact-abrasive wear resistance, and its wear resistance has arrived at, even pass beyond austenitic manganese steel and high chromium cast iron. Moreover, its wear mechanism appears as microcracking and microploughing.