Among the bulk metallic glasses, the Cu-Zr-Al system has been known as one of the best glass former systems, however, their low ductility hinders their effective applicability. Therefore the addition of rare-earth elements and production of amorphous/crystalline composite (ACC) materials by in situ by ex-situ methods provide better mechanical properties compared to their monolithic amorphous or crystalline alloys. This study focuses on synthesis and development of Cu-Zr-Al-Sm amorphous and amorphous/crystalline nanocomposite alloys, and the investigation of thermal stability, crystallization kinetics and mechanical properties of Sm microalloyed Zr-Cu-Al bulk metallic glasses and their nanocomposites using combined characterization techniques including differential scanning calorimetry (DSC), X-ray diffraction (XRD), electron microscopy and hardness and compression tests. In this study we will present and discuss the devitrification dynamics and crystallization kinetics under both continuous and isothermal annealing conditions, hardness, and compression tests. This work has been supported by TUBITAK under the grant number 117M295.