In this paper, the latest research development on the heat treatment processes, microstructure and mechanical properties of low-carbon martensite steel was reviewed. And the effects of heat treatment processes on the microstructure and mechanical properties of low-carbon martensite steel were analyzed.

β-Sialon powder was synthesized by in-situ carbothermal reduction-nitridation process, with fly ash and carbon black as raw materials. The influence of raw materials composition on synthesis process was investigated, and the phase composition and microstructure of the synthesized products were characterized by X-ray diffraction and scanning electronic microscope. The carbothermal reduction-nitridation reaction process was also discussed. It was found that increasing carbon content in a sample could promote the decomposition of mullite in fly ash and the formation of β-Sialon. The β-Sialon could be synthesized at 1550°C for 6h by heating the sample with the mass ratio of fly ash to carbon black of 100:56. The β-Sialon as-received in this study existed as granular with an average particle size of about 2μm. The carbothermal reduction-nitridation reaction process consisted of the nitridation processes of mullite, SiO2and Al2O3in fly ash as well as the conversion process of X-Sialon to β-Sialon.

The latest development of ZrC-SiC, ZrO2-SiC and ZrO2-mullite high performance composites synthesized from zircon was reviewed. The future development of synthesizing high performance composites from cheap materials and simple preparation technology was prospected.

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The corundum based material was prepared, with fused white corundum, commercial SiC powder and superfine Al2O3-SiC powder synthesized from clay by carbothermal reduction reaction as raw materials. The influences of SiC and Al2O3-SiC powders on the slag penetration and corrosion resistance of the material were investigated, and the slag resistance mechanisms of the additives were also discussed. It was found that the slag resistance of the corundum material by adding Al2O3-SiC and SiC powders could be improved obviously. For improving the slag resistance of the corundum material, adding Al2O3-SiC was much better than adding commercial SiC. When the Al2O3-SiC powder contacted with the molten slag, Al2O3 in the additive could be dissolved into the molten slag immediately, while SiC remained, which caused the viscosity of molten slag to be increased. So, the slag penetration and slag corrosion into the corundum material could be effectively inhibited.