Fabrication of in situ Al2O3 reinforced nanostructure 304 stainless steel matrix composite by self-propagating high temperature synthesis process

• Fe2O3–Cr2O3–NiO–Al–Fe system was used for synthesis of 304 stainless steel.
• A composite was produced by self-propagating high temperature synthesis.
• The composite contains Al2O3 reinforcements in the 304 stainless steel matrix.

304 austenitic stainless steel reinforced by Al2O3 particles was prepared by microwave assisted self-propagating high temperature synthesis process using the Fe2O3Cr2O3NiOAlFe reaction system. Furthermore, effects of mechanical activation of the reactants and the addition of 21.2 wt.% extra Al to the chemical composition of the reactants on the chemical composition of the produced stainless steel was investigated. Atomic absorption spectroscopy analysis results indicated that by the addition of extra Al to the reactant mixture and using 30 minute mechanical activation, stainless steel containing 17.27 wt.% Cr and 7.73 wt.% Ni could be produced with its chemical composition very close to the chemical composition of 304 stainless steel. X-ray diffraction analysis showed that the stainless steel contains nanostructured austenite and ferrite phases. Also microstructural characterizations indicated that there is a uniform distribution of black particles in the steel matrix. Energy dispersive spectroscopy analysis showed that these particles are composed of Al and O elements while the matrix contains Fe, Cr and Ni elements. The presence of Al2O3 particles and nanostructure matrix improved the hardness and therefore the wear properties of the composite in comparison with the wrought 304 stainless steel plate.

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