EXPERIMENTAL CHARACTERIZATION OF AN INNOVATIVE COPPER-MARAGING STEEL METAL-MATRIX-COMPOSITE MATERIAL FOR A LIQUID ROCKET ENGINE THRUST CHAMBERS BY L-PBF ADDITIVE MANUFACTURING

Thrust chamber of high performance bi-propellant liquid rocket engines is a critical component of the launch vehicles. The requirement of reducing the temperature of the walls exposed to the hot gas can be met with high-thermal conductivity copper alloys while the mechanical stiffness is achieved by using high strength steel or nickel alloys. Because the stress–strain behavior of a regeneratively cooled thrust chamber is directly correlated with its temperature behavior, it is of primary importance to select an adequate alloy. A new copper-steel metal matrix composite, processed by L-PBF additive manufacturing, is proposed. A patented innovative additive manufacturing powders mixing process is used. A thermal, mechanical and fatigue characterization of the new composite was performed. A new time dependent material behavior has been pointed out. It is a “local hill softening-hardening phenomenon”, which is a time dependent activated damage which occurs during cycling and creep tests at high temperature.