Effect of cold and warm rolling on the particle distribution and tensile properties of heterogeneous structured AlN/Al nanocomposites

Abstract

Recently, heterogeneous structured metals have attracted extensive interest due to their exciting mechanical properties. In this work, an AlN/Al nanocomposite with heterogeneous distribution of AlN nanoparticles was successfully prepared by a liquid-solid reaction method combined with subsequent extrusion deformation, which behaves an excellent synergy of tensile strength and ductility. In order to further reveal the particle distribution evolution and the tensile property response during further deformation, a series of rolling treatments with different thickness reductions under room temperature and 300 °C was carried out. The results show that the yield strength and tensile strength of the composites increase significantly from 238 MPa, 312 MPa to 312 MPa, 360 MPa after 85% rolling reduction at 300 °C. While the elongation decreased from 15.5% to 9.8%. It is also noticed that the elongation and tensile strength of the nanocomposites increases simultaneously with increasing deformation. It is considered that the aluminum matrix strengthening effect accounts for the strength enhancement. The AlN spatial distribution in the matrix becomes more homogeneous gradually during the rolling, which is supposed to reduce the stress concentration between the particle and matrix and then promote the ductility increase.