The microstructure of Cu—13.0Al—3.9Ni—0.4Ti—0.2Cr wt.% compacts sintered by spark plasma method from powders prepared by spark-erosion method in liquid argon from master alloy is investigated. Powder is annealed in H$_{2}$ atmosphere before the spark plasma sintering. SEM and TEM investigations reveal that sintered samples have a composite structure, which consists of the micron and submicron spherical metallic particles embedded into the binder matrix. This matrix seems to be the product of copper oxide reduction according to the scheme CuO → Cu$_{4}$O$_{3}$ → Cu$_{2}$O → Cu$_{8}$O and aluminium hydroxides’ conversion according to the flowchart aluminium hydroxide → transition alumina → $\alpha$-Al$_{2}$O$_{3}$, during the annealing and/or sintering. TEM study reveals that main phase in metallic particles is self-accommodated 18R martensite. The regular basal plane stacking faults and/or (001)$_{18R}$ microtwins are dominant defects in 18R martensite. 18R martensite of single orientation occupies entire volume of spherical nanoparticles, being the basal plane stacking faults and/or (001)$_{18R}$ microtwins, which have different thicknesses.