Microstructure-properties correlation of pressure die cast eutectic aluminum–silicon alloys for escalator steps (Part II)

The work reported is the continuation of Part I, in which the microstructure of the commercial Al–12%Si alloy was altered by the addition of modifier and/or refiner elements to the melt to improve the alloy's mechanical properties. The goal in Part II was to characterize the mechanical properties produced by the different microalloying conditions generated for the Al–12%Si alloy in actual escalator steps. The experimental results confirm the improvement of properties in all alloy conditions, evidenced at a microstructural level through significant changes in the dispersed phases and the matrix. The competence of both the modifier (Sr) and the refiner (Ti) is underscored with regard to the volume fraction, the size and the morphology of the phases present. However, the best alloy results were obtained in the modified and refined condition at the highest rate Ti level chosen from among the selected compositional designs.