Microstructure refinement of melt-grown Al2O3/YAG/ZrO2 eutectic composite by a new method: Melt superheating treatment

The impact of the composition and solidification rate on the microstructure and the crystallographic orientations of Al2O3–YAG–ZrO2 eutectic solidified by the micro-pulling down technique

“…Whatever the composition, an overheating of the melt up to 2000 C was not accompanied by the formation of YAlO 3 perovskite as it was observed in previous works using the EFG and oating zone methods. 24,25,67,68 According to these results, there is a variety of microstructural features, which can be expected to be the cause for the different growth velocities and chemical compositions. For eutectic composition, Chinese script eutectic growth was observed from low to moderate growth rate and colonies for higher velocities.…”

The effect of superheat on the nucleation undercooling of metallic melts

“…The melt superheating treatment is widely applied in metal casting such as steel, iron, and magnesium and their alloys because of its impacts on the nucleation process of the melt. [1][2][3][4][5][6][7][8] This in turn determines the microstructures of as-cast metals. Du et al 1 found the melt structure turned to be homogeneous, and the glass-forming ability was enhanced as the Al 84 Ni 10 La 6 alloy subjected to the superheating treatment.…”

“…Ge et al 2 found that the dendrites were refined as well as the γ 0 phase while the DZ125 superalloy was superheating treated. Fu et al 3,4 were successfully to refine the microstructure of bulk eutectic Al 2 O 3 /YAG/ZrO 2 by adopting melt superheating. Nader 5 and Chen et al 6 observed the superheating has influenced the morphologies of solid/liquid interface and remarkably determined the geometries of the primary phase, thus leading to the excellent mechanical properties in consequence of such refined microstructures.…”

Insights into the ternary eutectic microstructure formed in intercolony regions in Al2O3–ZrO2(Y2O3) system

“…These composites consisting of two or more single crystal phases with the clean and strong interfaces possess outstanding high‐temperature mechanical properties, superior creep resistance, and excellent chemical stability. Therefore, they have been considered as the most promising candidates for the thermomechanical applications at the high temperature …”

“…The larger volume products with the high‐temperature gradient would generate the larger thermal stresses, especially on the surface of crystals. It might induce the intensive thermal strains and cracks occur . These above disadvantages greatly impede the industrial application of the Al 2 O 3 /ZrO 2 (Y 2 O 3 ) composites.…”