Microstructures and mechanical properties of Al2O3/YAG:Ce3+ eutectics with different Ce3+ concentrations grown by HDS method

Abstract

The Al2O3/YAG:Ce3+ eutectics (170 mm × 90 mm × 20 mm) with different Ce3+ concentrations, which could be used as structural members and new type of fluorescent materials, were grown by the horizontal directional solidification method. Variations in the microstructures of the eutectics, such as the three-dimensional cross distribution of coarse and fine microstructure regions caused by Ce doping, were directly presented by μCT. The residual compressive stress in the Al2O3 phases increased with the increase of Ce concentration in the eutectics. Although the Young’s modulus, Vickers hardness, and fracture toughness of our eutectics decreased slightly with the increase of Ce concentration, the values were still in the range of the prior results. The flexural and compressive strength of the eutectics were also measured from room temperature to 1273 K. The flexural strength of these eutectics decreased with an increase in Ce concentration. But the eutectic with Ce/Y = 0.25% exhibited a higher compressive strength (1946 MPa) compared to that of the eutectic with Ce/Y = 0% (∼1200 MPa). Therefore, the controlled use of the Ce ions additive is an attractive option to improve the compressive strength of the Al2O3/YAG eutectics.