Microstructure of Glidcop AL-60

Abstract

Glidcop is an oxide-particle-dispersion strengthened copper composite that has a combination of high mechanical strength and high electrical conductivity. It has been used as a conductor for the 100 T ultrahigh field pulsed magnet by the National High Magnetic Field Laboratory, USA. In the quest for even higher field pulsed magnets, material development is crucial. Since the mechanical properties of a material are often determined by its microstructure, full characterization of the microstructure of Glidcop is necessary. In this work, we studied the microstructure of Glidcop AL-60 using both transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM). We identified both α-Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> and cubic η-Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> nanoparticles in AL-60 and investigated their size and density distribution. The η-Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> nanoparticles with typical size of 5 to 30 nm are of triangular shape. They have well defined crystal orientation relationship with the Cu matrix. We observed dislocations pinned by the alumina nanoparticles in cold-drawn wires. We believed that dislocation bypassing alumina particles via Orowan looping was the main strengthening mechanism. We observed microcracks near large particles, demonstrating the detrimental effect of large particles in AL-60.