Mechanical Properties of La–Ce-Substituted Nd–Fe–B Magnets

Influences of La-Ce substitution on the microstructure and mechanical properties of R2Fe14B-type (R: rare earth) permanent magnets have been investigated. The results show that the optimum compressive and bending strengths of 1137.8 and 339.9 MPa, respectively, are achieved at 18 wt.% La-Ce substitution for Pr-Nd. La-Ce substitution is found to enhance the micro-hardness and Young's modulus of 2:14:1 matrix phase gradually, strengthening the main phase grains. The irregular grain growth together with weakened R-rich intergranular phase in higher La/Ce-containing magnets, however, leads to easier crack propagation, hence deteriorating the mechanical properties. Consequently, R-Fe-B permanent magnet with a proper La-Ce content satisfies the constraints of cost, and magnetic and mechanical properties simultaneously, thereby exhibiting competitive advantages for mass production.