The phase equilibrium and phase transformation of the Al–Si–Y ternary system were investigated in 80 annealed alloys using an electron probe microanalysis (EPMA), X-ray diffractometry (XRD) and differential scanning calorimetry (DSC). The phase equilibrium at 773 K was determined, and the phase distribution and solid solubility of the Al–Si–Y isothermal section at 773 K were obtained. A total of 23 three-phase zones and 4 two-phase zones were obtained, and 2 new ternary compounds, AlSi4Y5 and Al2Si3Y5, were identified from the non-aluminum-rich corner. Additionally, the phase transition temperatures of representative alloys were determined by the DSC method, and then the phase transition temperatures were processed to obtain the experimental points of vertical sections. In the Al–Si–Y alloy system, the phase diagrams of the vertical sections with X(Al) = 90 at.%, 80 at.%, 70 at.% and 60 at.% at the aluminum-rich corner were calculated, and then the experimental points were inserted into the vertical section phase diagrams. The results of the vertical sectional experiments obtained from the validation experiments are in good agreement with the vertical sectional data obtained from the calculations, indicating that the validated thermodynamic description is useful for the microstructure design of the aluminum-rich corner of the Al–Si–Y ternary alloy.

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The isothermal section of the La–Co–Ni ternary system at 723 K has been constructed in this work by using X-ray diffraction (XRD), scanning electron microscopy, and energy dispersion spectroscopy techniques (SEM-EDS). The experimental results show no existence of ternary compounds at 723 K. The isothermal section consists of 16 two-phase regions and 8 three-phase regions. La3Co and La3Ni, La2Co3 and La2Ni3, La2Co7 and La2Ni7, and LaCo5 and LaNi5 form a continuous solid solution. The ternary solid solubility of Ni in LaCo13 phase and La2Co1.7 phase was determined to be 15.61 at.% and 9.61 at.%, respectively. The solid solubility of Co in the LaNi3, La7Ni3, and LaNi phases was 18.07 at.%, 5.62 at.%, and 8.49 at.%, respectively. The present experimental results are important for the design of La(Fe,Si)13-based magnetic refrigeration materials.

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