Effect of Combined Addition of Trace Sc and Zr Elements on Mechanical Properties and Corrosion Behavior of B₄C/7075Al Composite

Abstract

The key to restrict the engineering application of high-strength B4C/Al composites is corrosion, and adding trace alloying elements is an effective measure to improve corrosion resistance. In this work, the B4C/7075 and B4C/7075-0.15Sc-0.35Zr composite containing trace Sc and Zr elements were prepared by pressure infiltration. The influence of combined addition of Sc and Zr on microstructure, mechanical properties and corrosion behavior of B4C/7075 composites was investigated by using scanning electron microscopy, transmission electron microscopy, bending performance testing, tensile performance testing, neutral salt spray testing and electrochemical testing. Results showed that adding Sc and Zr elements to B4C/7075 composites, the higher bending strength and tensile strength values were obtained in B4C/7075-0.15Sc-0.35Zr. In addition, the corrosion rate and the corrosion current(Jcorr) decreased, indicating that the corrosion resistance of B4C/Al composite increased, which might be caused by that the grain boundary precipitates in the composite material were small and discontinuous after adding Sc and Zr elements, and the precipitate free zone(PFZ) disappeared.

Keywords

• b₄c/7075 composite; sc; zr; mechanical properties; corrosion behavior; pfz