Mechanical properties and corrosion resistance enhancement of 2024 aluminum alloy for drill pipe after heat treatment and Sr modification

Aluminum drill pipes have high specific strength but poor wear resistance, which often results in the failure of the pipes in field applications, owing to wear and corrosion. In this study, the 2024 aluminum alloy was modified with Sr and then strengthened with heat treatment. The strengthening effect of the alloy after combined strengthening treatment was discussed and evaluated by microstructure observation and characterization, mechanical property test, and corrosion test. The results show that the intermetallic phase precipitates from the 2024 aluminum alloy matrix after artificial aging, which produces a dispersion-strengthening effect. Meanwhile, Sr refines the phase particles precipitated during artificial aging, improves the dispersion strengthening effect, and further strengthens the mechanical properties. In addition, Sr inhibits the growth of copper-rich second phase particles in the 2024 aluminum alloy and increases the elemental copper content of the matrix. The increased copper content in the matrix further increases the corrosion resistance and strength. The results prove that the combined treatment of heat treatment and Sr modification is feasible for the comprehensive strengthening of 2024 aluminum alloy for drill pipes.