Effect of microstructure on the mechanical and corrosion behaviors of a hot-extruded nickel aluminum bronze

摘要

In this paper,the influence of microstructure on the corrosion behavior of a hotextruded nickel aluminum bronze was studied.Three kinds of samples subjected to the hot-extrusion,annealing and quenching conditions were prepared and immersion tests in 3.5% NaCl solution were carried out.Microstructures and corrosion surface morphologies of the samples were observed by SEM.It was found that the retained β martensite and(α+κⅢ) lamella eutectoid in the as hot-extruded material were eliminated after annealing,and corrosion resistance of the alloy was improved.As to the as-quenched material,its corrosion rate was higher than that of the as hotextruded material since the volume fraction of β phase which was anodic to α phase increased after quenching.As regards the mechanical properties,the as-quenched sample possesses the highest hardness and tensile strength among the three kinds of samples,while the as-annealed sample possesses the highest elongation.That is to say,heat treatment plays different roles in the mechanical properties and corrosion resistance of the experimental alloy.