This study investigates the mechanical properties of aluminum alloys AlSi10Mg and AK9ch fabricated by selective laser melting (SLM), taking into account the build orientation (longitudinal, transverse, 45°) and applied heat treatment regimes (stress-relieving annealing, T6 treatment, prolonged aging). A comprehensive tensile test program was conducted to determine ultimate tensile strength, yield strength, elongation, and hardness. Results show that SLM-processed specimens significantly outperform conventionally cast AK9ch, especially after T6 treatment, achieving up to 285 MPa in strength with ~9% elongation. For the first time, it is demonstrated that the Russian casting alloy AK9ch is suitable for SLM technology, with post-treatment strength reaching 259 MPa and ductility ~5%, comparable to that of AlSi10Mg. The influence of build orientation was found to be negligible at high relative density (>99%). The findings confirm the potential of additive manufacturing to produce high-performance aluminum parts using domestic alloys, offering a promising path toward import-independent 3D production in Russia.