Effect Y addition on the microstructure and micro hardness of Zr-Mo-Cr alloy for SMR structural cladding material

Effect Y addition on the microstructure and microhardness of Zr-Mo-Cr alloy for SMR structural cladding material has been studied. Synthesis of Zr-Mo-Cr with different Y content was carried out by a single arc melting furnace. After melting, the zircalloys were characterized by X-ray diffraction and SEM/EDS. The hardness of the zircalloys was tested by the Vicker's microhardness. In this study, characterization by optical microscope showed that the microstructure of Zr-Mo-Cr and Zr-Mo-Cr-Y zircalloys are relatively similar. The microstructure of the ternary zircalloy Zr-Mo-Cr and Zr-Mo-Cr-Y is consisting of dendritic with inter-dendritic contain intermetallic. The hardness test results show that the addition of Yttrium to Zr-Mo-Cr with different Y content increased the hardness of the Zircalloy. The Zr- Mo-Cr-0.5wt.% Y was performed the highest hardness. X-ray diffraction of the zircalloys depicted that as cast Zircalloys showed dominated by α phase and intermetallic.