DS copper alloys contain a fine dispersion of nanometer-sized oxide particles such as alumina, zir — conia, hafnia, or chromia in the copper matrix, giving rise to high-strength and thermal stability of the alloys. This class of copper alloys can be manufactured by either conventional powder metallurgy or internal oxi­dation. Their properties strongly depend on the type, dimension, and volume fraction of the dispersed phase and processing techniques. Unlike PH copper alloys, the addition of finely dispersed oxide particles into the copper matrix can prevent recrystallization of the matrix and consequent softening even after exposure to temperatures approaching the melting point of the copper matrix. In addition, the oxide particles are insoluble in the solid state, and are essentially immune to coarsening because of their high melting point and high thermodynamic stability. This extends the useful temperature range of a DS alloy far beyond that possible for conventional PH alloys.

Several DS copper alloys have been evaluated for fusion applications, for example, GlidCop® Al15, Al25, Al60, and MAGT 0.2. Both GlidCop® and MAGT class alloys are strengthened by Al2O3 particles, produced by internal oxidation. GlidCop® Al25 and MAGT-0.2 have been studied extensively because of their balanced strength, thermal conduc­tivity, and ductility. GlidCop® Al25 (0.25 wt% Al) is produced by OMG America. CuAl25-IG is the ITER grade with the optimized fabrication process for improved ductility and reduced anisotropy. The microstructure of the CuAl25 alloy is characterized by elongated grain structure along the extrusion or rolling direction and a high density (average of 3.27 x 1022m~3) of dispersed Al2O3 particles with a mean diameter of 6-9 nm. The distribution of alumina particles can be highly heterogeneous, with some grains free of strengthening particles. A low number density of micron-size a-Al2O3 particles exists at grain boundaries. The density of dis­locations in the as-wrought condition can be as high as ~1.5 x 1015m~2.15-18,22-24 Most of the oxide particles in GlidCop alloys are triangular platelets with the remainder in the form of circular or irregular-shaped disks.25

MAGT 0.2 is a Russian alloy produced by SPEZS — PLAV Company. It contains 0.17% Al, 0.05% Hf, and 0.09% Ti in the form of oxide particles.25,26 GlidCop contains Al-oxide particles only, while in MAGT alloy, there are Al-, Ti-, and Hf-oxide particles, and mixed Al — and Ti-oxide particles. A majority of the oxide particles in MAGT 0.2 are spherical in shape with a small fraction in the form of circular disks, with an average particle size of 6 nm.25,26