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The Al-13.6Cu-6Si (wt.%) ternary alloy was solidified upward unidirectional directionally in a Bridgman-type directional solidification furnace at a constant solidification rate (V=17.4 μm/s), different temperature gradients (1.6-6.12 K/mm), and different solidification rates (8.3-166.0 μm/s) at a constant temperature gradient (G=4.64 K/mm). After completion of the solidification process, the alloy samples were subjected to metallographic treatments to reveal their microstructures. The effect of solidification parameters (V and G) on microstructure parameters (λ1 and λ2) was examined. In addition, the dependence of microhardness on solidification rate, temperature gradient, and microstructure parameters was investigated. The results were also compared with similar experimental results reported in the literature. [ABSTRACT FROM AUTHOR]

In this study, Al50Si25B25 alloy was produced as ingot by arc melting method. The microstructure of the Al50Si25B25 alloy was investigated by X-ray diffraction (XRD), the morphological properties were investigated by scanning electron microscopy (SEM), and its thermal properties were investigated by differential thermal analysis (DTA) and differential scanning calorimetry (DSC). The mechanical properties of the alloy were investigated by Vickers microhardness (HV) test. The XRD result showed that B and Si atoms dissolved in the Al lattice to form the intermetallic phase of the a-Al (B, Si) solid solution. XRD and SEM results showed that the microstructure of the alloys consisted of a-Al(B,Si) solid solution, Si and AlB2 intermetallic phases. SEM results showed that the morphological structure of the alloys formed as dendritic and eutectic structures. DSC and DTA results showed an endothermic peak indicating the melting of the a-Al(B,Si) phase. The microhardness value of the alloy was measured as 108±15 HV at room temperature. This value increased as a result of the heat treatment and increased to 232±9 HV at 300 °C. It was observed that the microhardness value of the alloy decreased at temperatures higher than 300 °C. [ABSTRACT FROM AUTHOR]