STRUCTURAL FEATURES, MECHANICAL PROPERTIES, AND TRIBOTECHNICAL PERFORMANCE OF HOT-FORGED Fe–Cr–C(B) POWDER COMPOSITES 

Abstract

The influence of the starting charge composition and forging process parameters on the structure, mechanical properties, and tribological performance of powder composites based on the Fe–Cr–C(B) system was studied. The composites were produced by hot forging of porous preforms prepared from a mixture of iron, ferrochrome, and titanium diboride powders. The structurization and mechanical properties of the composites were found to be primarily influenced by the production technology. It was also demonstrated that products with tailored functional properties could be fabricated by adjusting the technological parameters. The research findings showed that the content of doping elements in the starting charge significantly influenced the physical and mechanical properties of the final products. The structure of composites produced by hot forging of porous preforms was similar to that of composites produced by liquid-phase sintering. However, the elemental composition of the structural components varied depending on the amount of TiB₂ in the starting charge.  An increase in the titanium diboride content led to a decrease in the titanium content in carboboride, from 45–55% to 5–11%, and to the redistribution of other elements. It was further established that raising the hot forging temperature from 1100 °C to 1200 °C reduced the hardness of the composite from 76–79 HRA to 70–71 HRA. The research allowed the determination of optimal technological parameters and charge compositions necessary to produce materials with low residual porosity and specified functional properties. These materials are intended for operation under high–load conditions or for the fabrication of tribological components.