Effect of extrusion parameters on microstructure, texture and mechanical property anisotropy of spray deposited 2195 Al–Li alloy profile

Abstract

To study the effects of extrusion parameters on the microstructure, texture, and mechanical property of 2195 Al–Li alloy, several extrusion experiments were carried out at different extrusion temperatures and speeds. A profile with different aspect ratios was designed, and the corresponding extrusion die was also designed and manufactured. The effects of aspect ratio, extrusion temperature, and speed on the microstructure and mechanical properties were investigated. The results show that cylindrical fiber grains and strong fiber textures of <111> and <100>//ED can be formed in the symmetrical areas with a low aspect ratio, which makes the profile at the areas have higher tensile strength along the extrusion direction and cause greater anisotropy of mechanical property. With the increase of aspect ratio, the grain structure turns into flat shape, and the fiber textures also change to {011}<211> and {011}<311>, the proportion of the {011}<311> texture component is higher at the area with a larger aspect ratio. This change in texture reduces the longitudinal strength of the profile and improves the transverse strength, which thus reduces the degree of anisotropy. As the extrusion temperature increases, the tensile strength of the profile can be increased due to the enhanced solution strengthening. However, excessive extrusion temperature will lead to obvious recrystallization and grain coarsening, which seriously reduces the formability and plasticity of the profile. Increasing the extrusion speed is beneficial to the dissolution of secondary particles into the matrix, which improves the strength of the profile. The grain size and recrystallization are little influenced by the extrusion speed. The increase of extrusion speed promotes the formation of the texture of {011}<311>, which improves the transverse strength of the profile and reduces the anisotropy.