The influence of adding different amounts of silicon carbide on the properties (density, transverse rupture strength, microhardness and corrosion resistance) and microstructure of low alloy steel was investigated. Samples were prepared by mechanical alloying (MA) process and sintered by spark plasma sintering (SPS) technique. After the SPS process, half of each of obtained samples was heat-treated in a vacuum furnace. The results show that the high-density materials have been achieved. Homogeneous and fine microstructure was obtained. The heat treatment that followed the SPS process resulted in an increase in the mechanical and plastic properties of samples with the addition 1wt. % of silicon carbide. The investigated compositions containing 1 wt.% of SiC had better corrosion resistance than samples with 3 wt.% of silicon carbide addition. Moreover, corrosion resistance of the samples with 1 wt.% of SiC can further be improved by applying heat treatment.

Low-alloy steels produced via the traditional powder metallurgy process, using a die compaction, are currently widely used. Therefore, improving their properties is an issue that attracts much attention. The most common method of enhancing the properties of a given material is introducing additives, e.g., silicon to prealloyed low-alloy steels. It may be added through the mechanical alloying process. The article presents the results of research focused on an analysis of the influence of: (1) the mechanical alloying process, (2) various amounts of silicon carbide: 1, 2 or 3 mass% and carbon addition: 0.4 or 0.6 mass%, (3) different atmospheres, reducing or inert with 10 mass% of hydrogen and (4) the effect of annealing on phenomena occurring during the sintering of low-alloy steel. Moreover, changes in the sinters' microstructure and microhardness were also investigated. Based on the results, it was found that an increase in the amount of silicon in the material causes an increase in the shrinkage of the samples, prepared using mechanical alloying, during the sintering process. This observed effect was independent of the carbon content (0.4 or 0.6 mass%) in the samples as well as of the sintering atmosphere (reducing or inert with 10 mass% of hydrogen). The smallest porosity was observed for samples sintered directly after the mechanical alloying process. There is no need to use a hydrogen atmosphere during sintering—10 % of hydrogen added to an inert, e.g., helium atmosphere is enough to sinter the samples correctly.

The addition of silicon to low-alloy steel allows to modify the materials' microstructure and thus to improve their corrosion resistance and mechanical properties. The influence of adding different amounts of silicon on the properties (density, transverse rupture strength, microhardness and corrosion resistance) and microstructure of low-alloy steel was investigated. Samples were prepared via the mechanical alloying process, which is the most useful method to homogeneously introduce silicon to low-alloy steel. Sintering was performed by using the spark plasma sintering (SPS) technique. After the SPS process, half of each of the obtained samples was heat-treated in a vacuum furnace. The results show that high-density materials were achieved, and a homogeneous and fine microstructure was obtained. The investigated compositions containing 1 wt% of silicon had better corrosion resistance than samples with 3 wt% of silicon addition. Furthermore, corrosion resistance as well as the mechanical and plastic properties of the samples with 1 wt% of silicon can be further improved by applying heat treatment.