Composites are solid materials consisting of a matrix and reinforcement. Due to their versatility and superior properties, aluminium matrix composites (AMC) are widely
used in industry and are still the subject of interest for many researchers. Among aluminium composites, the composite reinforced with particles of the Mg2Si intermetallic phase (Al-Mg2Si) is the most popular due to its low density and high hardness at the same time, high melting temperature and low thermal expansion coefficient. The intermetallic reinforcing Mg2Si phase is formed "in-situ" in the composite manufacturing process, which is possible with simple casting techniques. Coarse particles of the reinforcement phase of irregular shapes in the as-cast state which are formed during "in-situ" production mainly reduce the tensile strength and ductility of the final composite. The mechanical properties and microstructural disadvantages can be improved by homogenization annealing. The homogenization
process is a heat treatment that eliminates low-melting eutectics and crystalline precipitates, changes the shape of the intermetal phases, and creates uniformly distributed, fine hardening precipitates.
The purpose of the master's thesis was to synthesize, homogenize and characterize Al-Mg2Si composite samples after 4, 12, 24, 48 and 96 hours of homogenization treatment in an electric resistance furnace at 430 and 520 °C. We plotted the equilibrium phase diagram and Scheil curves in the Thermo-Calc program. We also performed simple thermal analysis (ETA) and plotted cooling curves in the Origin program and differential scanning calorimetry (DSC). Microstructural characterization was also performed to define the type, proportion and morphology of phases in the as-cast and homogenized samples.
The results of DSC and metallographic analysis showed that the primary Mg2Si phase, eutectics (αAl + Al13Fe4), (αAl + Mg2Si) and (αAl + Mg2Si + βSi) are present in the as-cast
and homogenized samples. Only the sample in the as-cast state still contains the eutectic (αAl + β-Al3Mg2) at a lower temperature which disappears after homogenization. The polygonal particles of the primary Mg2Si phase begin to become rounder after 24 hours of homogenization and after 96 hours they are noticeably rounder. As the homogenization time increases, the eutectic (αAl + Mg2Si) also becomes finer and rounder.
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