The Young’s modulus of an Al-Si-Mg-Cu alloy reinforced with TiB2 and Mg2Si was investigated under different heat treatment processes, including T4, T6, T7 and O temper. The microstructural evaluation and mechanical properties of the developed Al-Si-Mg-Cu alloy was examined by X-ray diffractometer (XRD), optical microscopy (OM), scanning and high resolution transmission electron microscopies (SEM and HRTEM), ultrasonic pulse technique and tensile test. The results revealed that the alloys, in all heat treatment conditions, consist of Si, Mg2Si and TiB2 phases, which are responsible for the increase of Young’s modulus. HRTEM micrographs showed the formation of incoherent, clean and smooth interfaces between aluminium matrix and TiB2 particles. The alloys with 93 GPa Young’s modulus are still castable for making shaped castings. In comparison with the conventional aluminium alloys that have Young’s modulus at a level of 70 GPa, 30% increase of Young’s modulus can be achieved by the developed alloys.