| Because of good merits in cost reducing, enhancing performance and craft simplification, the research and the application on casting surface alloying (compound materials) obtains more and more many attention and development in recent years,. Because TiC has these characteristics such as high degree of hardness, high module and the good chemical stability etc, it has been widely applied as an in-situ reinforcing phase in metal-based compound materials.In this research , in the condition of pressure 30MPa, the vacuum degree-0.06MPa, the SHS (Self-propagating High-temperature Synthesis) technology is utilized to produce the TiC/Fe steel-based surface compound material; simultaneously in the compact of SHS had been mixed separately by with 5%, 15%, 20% MnFe powder and 10%, 20%, 30%, 40% CrFe powder. Observation and analysis on the differences of the microstructure and properties of TiC/Fe composite materials after mixed different content alloying element of Mn, Cr is done carefully, especially the influence on microstructure and hardness of TiC/Fe composite materials for the change of TiC particles. And through suitable heat treatment, further observetion and research on the influence of heat treatment on the SHS composite materials microstructure and the change of x value in TiCx particles. Through controlling matrix organization and its performance, the influence on the TiC/Fe composites microstructure and mechanics performance by mixed alloying elements Mn and Cr separately. The results indicated that:Because mixed Mn and Cr alloying element, the temperature in the course of self-propagation high temperature synthesis is reduced obviously, this causes the size, shape and performance of the composite materials different from those unmixing with Mn and Cr alloying element. Alloying element Mn, Cr exist in the alloying cementite and the Fe substrate, as a diluent, it has the obvious refinement function of TiC pellet; also alloying element Cr refining TiC pellet function is more obvious than mixed alloying element Mn.The mixing of alloying element MnFe, CrFe reduces the Ti content in the compact of SHS, which causes the hardness of the TiC/Fe steel matrix surface composites reducing, but because alloying element Mn, Cr disffused to substrate and producing the alloy cementite, enhanced the hardness of matrix, the hardness grade of the composites coating and the substrate was improved.The TiC particles in TiC/Fe composites partly decomposed in the heat treatment,but hardness of the composites and the substrate changed slightly, because the Ti andthe C element decomposed form TiC in the matrix formed twice tiny TiC particles. |
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