Influence of the Addition of Strontium on Eutectic Aluminium Alloys

This paper studies the effect of strontium on eutectic aluminium alloy (LM6) and its mechanical properties, with the aim of impacting high strength and ductility. Four alloy samples of LM6 with varying amounts (0%–0.1%) of strontium were cast. Universal tensile and Micro Vickers hardness testing machines were used to determine the alloy’s mechanical properties (tensile strength and percentage elongation) and hardness. An optical microscope was used to analyse the alloy’s microstructure. The results showed a reduction in hardness and an improvement in tensile strength and percentage elongation. The alloy with 0.05 wt% of strontium recorded the best results in tensile strength (232.24 ± 12 MPa), and this represents an improvement of 17.4% compared with the neat alloy (197.89 ± 10 MPa), and the same trend was observed for its percentage elongation, with an improvement of 3.52% compared with the neat alloy. ImageJ software statistical analysis showed that the mean average grain size of the detected phases ranges between 31.298 and 33.063 μm, while optical microscopic analysis showed that the addition of strontium to eutectic Al–Si alloy changes the Al–Si eutectic structure which resulted in the alloy’s mechanical properties enhancement, and the alloy is a suitable candidate for stress applications within 200–232 MPa.