Effects of Al, V, Cr, Mn, Ni, Nb, Mo, and W Addition to BCC-Fe on its Elastic Properties and Hardness for a Biomass Boiler: First Principles Approaches

초록

During biomass combustion for renewable energy generation, combustion byproducts such as fly ash and metal chlorides cause serious erosion problems in boilers, as well as corrosion. To develop a highly wear-resistant composition of alloy for biomass boilers, we investigated how the addition of various metallic elements to BCC-Fe affected its elastic properties using first principles calculations. The added elements were Al, V, Cr, Mn, Ni, Nb, Mo, and W. These elements used to be included in T91 and T92 steels, which are considered suitable materials for biomass boilers. Our results revealed that except for Al and Ni, all of the other elements increased shear and Young's moduli, implying high wear-resistant characteristics. In contrast, all of the added elements decreased bulk modulus. Furthermore, V, Cr, Nb, Mo, and W increased atomic bonding strength and thus the escape energy of Fe atoms, leading to hindrance of corrosion by metal chlorides, too. To design a highly wear-resistant BCC-Fe alloy for biomass boilers, the additive elements and their amounts are important, in the order of Mn, Cr, Mo, W > V, Nb >> Al, Ni. We expect that the present results will provide a basic guideline when developing Fe-based materials with superior elastic and mechanical properties for biomass renewable energy generation.

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