Effect of ball milling time on characteristics of ZrC‒FeCrAl powders and mechanical properties of alloys

To enhance the mechanical properties of FeCrAl alloys, the nano ZrC particle dispersion strengthened FeCrAl (ZrC‒FeCrAl) alloys were prepared by mechanical ball milling and spark plasma sintering (SPS). The effects of ball milling time on the powder characteristics and the alloy mechanical properties were investigated. Scanning electron microscope (SEM), transmission electron microscope (TEM), oxygen content analysis, particle size analysis, X-ray diffraction (XRD) analysis, hardness tests, and tensile property tests were carried out. The results show that, prolonging the milling time is conducive to the refinement of powder particles. However, the higher oxygen content may lead to the deterioration of mechanical properties after sintering. After milling for 30 h, the average particle size of the powders is about 72.88 μm, and the oxygen content (mass fraction) is the lowest, which is 0.14%. The ZrC‒FeCrAl alloys prepared by SPS show the better mechanical properties after milling for 30 h, the ultimate tensile strength, elongation, and Vickers hardness reach 1046 MPa, 12.1%, and HV 349.9, respectively. The results confirm that, the addition of nano ZrC particles can notably improve the strength of FeCrAl alloys, which is of great significance for the practical application in the accident resistant fuel cladding materials.