Microstructure and Mechanical Properties of Ni-20Cr-Eu(2)O(3) Composites Prepared by Vacuum Hot Pressing

Ni-20Cr-Eu(2)O(3) composites were designed as new control rod materials and were synthesized from Ni, Cr, and Eu(2)O(3) mixture powders via ball milling and vacuum hot pressing. During ball milling, Eu(2)O(3) was fined, nano-crystallized, amorphized, and then dissolved into matrix. The effect of Eu(2)O(3) content on the microstructure and mechanics was researched, and the corresponding mechanism was discussed. The relative densities, grain sizes, and microhardness increased when Eu(2)O(3) content increased. According to the TEM observations, Eu(2)O(3) particles showed a semi-coherent relationship with the matrix. The results of mechanical property testing showed that the ultimate tensile strength, yield strength, and elongation decreased with the Eu(2)O(3) content increased. The maximum ultimate tensile strength, yield strength, and elongation were 741 MPa, 662 MPa, and 4%, respectively, with a 5 wt.% Eu(2)O(3) addition. The experimental strengths were well matched with the theoretical values calculated by the strengthening mechanisms indicating that this method was highly effective for predicting the mechanical properties of Ni-20Cr-Eu(2)O(3) composites.