Interface Stability of the SiC Particles/Fe Matrix Composite System

摘要

The interface reaction between the SiC particles (SiC_p) and Fe was studied during sintering the SiC_p reinforced Fe matrix composites at 1423 K for 1 h. In the composite having 3wt percent {weight ratio} SiC_p (the 3 SiC_p/Fe composite), the interface reaction products of Fe_3Si, the carbon precipitates, and Fe_3C or pearlite were generated. Fe_3Si constructs the bright matrix of the. reaction zone in the original situation of the SiC_p. The carbon precipitates are randomly embedded in the reaction zone. Fe_3C or pearlite exists at the grain boundaries of the Fe matrix. As increasing the SiC_p concentration in the SiC_p I Fe composite, the intensity of the interface reaction between SiC_p and Fe increases . After the 10 SiC_p I Fe composite {having 10 wt. percent SiC_p} sintered at 1423 K for 1 h , all of SiC_p are decomposed, and replaced by the reaction zone composed of Fe_3Si and the carbon precipitates. No Fe_3C or pearlite was generated during the reaction. The effects of the techniques of oxidizing of SiC_p, coating SiC_p by interaction with the Cr powder, and alloying the Fe matrix by adding the Cr element on the interface stability of the SiC_p/Fe composite system were also investigated, respectively. The oxide membrane and the coating layer on SiC_p can inhibit the interface reaction between SiC_p and Fe by isolating SiC_p from the Fe matrix during sintering. The interface reaction does not occur in the 3 SiC_p I Fe-10 Cr composite but in the 3 SiC_p/Fe-5 Cr composite. In the SiC_p/Fe-Cr alloy composites, the interface reaction between SiC_p and the Fe- Cr alloys is weaker than that between SiC_p and Fe. The Cr element behaves as a diluent, it causes a reduction in the interface reaction, which is proportional to the amount of the element added.