Hafnium influence on the microstructure of FeCrAl alloys

International Conference on Innovative Research - ICIR Euroinvent 2016

Geanta, V.^1 ; Voiculescu, I.^1 ; Stanciu, E.-M.^2

University Politehnica of Bucharest, Splaiul Independenei 313, sector 6, Bucharest

060042, Romania^1

S.C. Optoelectronica 2001S.R.L, str. Atomistilor, 409, Magurele

077125, Romania^2

关键词: Chemical characteristic;    Chemical compositions;    Experimental alloys;    Liquid metal environment;    Microstructural features;    Potential materials;    Protective oxide layers;    Vacuum arc remelting;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/133/1/012016/pdf
DOI  :  10.1088/1757-899X/133/1/012016

来源: IOP

【 摘 要 】

Due to their special properties at high temperatures, FeCrAl alloys micro-alloyed with Zr can be regarded as potential materials for use at nuclear power plants, generation 4R. These materials are resistant to oxidation at high temperatures, to corrosion, erosion and to the penetrating radiations in liquid metal environments. Also, these are able to form continuously, by the self-generation process of an oxide coating with high adhesive strength. The protective oxide layers must be textured and regenerable, with a good mechanical strength, so that crack and peeling can not appear. To improve the mechanical and chemical characteristics of the oxide layer, we introduced limited quantities of Zr, Ti, Y, Hf, Ce in the range of 1-3%wt in the FeCrAl alloy. These elements, with very high affinity to the oxygen, are capable to stabilize the alumina structure and to improve the oxide adherence to the metallic substrate. FeCrAl alloys microalloyed with Hf were prepared using VAR (Vacuum Arc Remelting) unit, under high argon purity atmosphere. Three different experimental alloys have been prepared using the same metallic matrix of Fe-14Cr-5Al, by adding of 0.5%wt Hf, 1.0%wt Hf and respectively 1.5%wt Hf. The microhardness values for the experimental alloys have been in the range 154157 HV0.2. EDAX analyses have been performed to determine chemical composition on the oxide layer and in the bulk of sample and SEM analyze has been done to determine the microstructural features. The results have shown the capacity of FeCrAl alloy to form oxide layers, with different texture and rich in elements such as Al and Hf.