Microstructure and Tensile Properties of 7N01 Aluminum Alloy Reinforced by In-situ ZrB₂ Nanoparticles and Rare Earth Sc

In-situ synthesized ZrB₂ nanoparticles and rare earth Sc were introduced to 7N01 aluminum alloy, the strength and ductility were enhanced via their synergistic effects. The investigation shows that the single introduction of in-situ ZrB₂ nanoparticles exhibits serious nanoparticle agglomeration, especially for the ZrB₂ content higher than 3wt%, which is detrimental to the mechanical enhancement of the composites. However, the further introduction of rare earth Sc can inhibit the serious agglomeration of ZrB₂ nanoparticles. Meanwhile, the addition of Sc can also modify the coarse Fe-containing precipitated phases, refine the matrix grains. With the combinatorial introduction of ZrB₂ and Sc, the strength and ductility of the prepared composites improve simultaneously compared with the corresponding 7N01 alloy. And the optimum content of ZrB₂ and Sc are 3wt% and 0.2wt% in this study, where the yield strength, tensile strength and elongation of the composites are 447 MPa, 481 MPa and 9.6%, increased by about 16.1%, 11.3% and 29.7% higher than that of 7N01 aluminum alloy matrix.