Tribological Behavior and Lead‐Bismuth Eutectic Corrosion Resistance of a Laser‐Cladding Fe 47.0 Cr 24.1 Mo 6.0
Yue Zhou, Jing Liu, Hui Huang, Xingming Yang, Yunpeng Fu, Lin Luo, Zhizhong JiangABSTRACT
A Fe 47.0 Cr 24.1 Mo 6.0 Nb 2.9 Ni 15.0 Al 5.0 high‐entropy alloy (HEA) coating containing Laves and B2‐NiAl phases was fabricated on 304 stainless steel substrates by laser cladding. Compared with the substrate, the coating exhibited increases of 88% in hardness and 75% in wear resistance by dry sliding tests in air at room temperature, 350°C, and 550°C for 30 min, mainly owing to the synergistic effects of dispersion strengthening and second‐phase strengthening. The corrosion behavior was investigated by exposure in lead‐bismuth eutectic (LBE) at 550°C with dissolved oxygen concentration of 1 × 10 −6 wt.% for 500, 1000, 1500, and 2000 h. After exposure, the coating formed a compact Fe 3 O 4 ‐FeCr 2 O 4 ‐Al 2 O 3 triple‐layer oxide scale with a thickness of less than 1 μm, which was approximately one‐tenth of that formed on the substrate under the same conditions. The B2‐NiAl phase promoted the formation of the protective oxide scale, whereas the Laves phase suppressed its excessive growth. These results provide a mechanistic understanding and technical guidance for the design of protective materials for key moving parts in lead‐cooled fast reactors (LFRs).