Enhancing Nuclear Fuel Cladding Performance: Optimizing SMAT Duration for Superior Hardness, Wear, and Corrosion Resistance in Zr-1%Nb Alloy

Zirconium alloys are vital for nuclear fuel cladding. Surface mechanical attrition treatment (SMAT) improves mechanical properties, with treatment duration playing a crucial role in grain refinement and corrosion resistance. This study examines SMAT’s impact on Zr-1%Nb alloy microstructure, hardness, and wear resistance. Samples were treated for 4, 8, and 12 min and compared to untreated ones. X-ray diffraction analysis revealed grain size reduction from 1.8 µm (untreated) to 0.76 µm (4 min), 0.43 µm (8 min), and 0.21 µm (12 min). SMAT also induced compressive residual stresses of 167 MPa (4 min), 186 MPa (8 min), and 225 MPa (12 min). Hardness increased from 220 Hv0.1 (untreated) to 282 Hv0.1 (12 min). However, surface roughness rose from 0.064  to 0.579 µm after 12 min. Corrosion resistance improved, especially with a passive coating, reducing corrosion rates. In conclusion, SMAT enhances Zr-1%Nb alloy properties—refining microstructure, increasing hardness, improving wear and corrosion resistance—despite higher surface roughness.