Improving contact damage resistance of spinel translucent ceramics through a multi-layer design

Abstract

The brittle response of transparent spinel ceramics to contact damage is limiting their application as an alternative to glasses and single crystals. In this work, we explore a strategy to enhance the contact damage resistance of spinel ceramics by embedding alumina layers in a multi-layer architecture. Crack initiation upon Hertzian indentation was investigated in MgAl2O4 - Al2O3 laminates and compared to their corresponding monoliths. Contact stresses during loading were analyzed using finite element simulations by considering the elastic properties of the layers and contact non-linearities. Results were analyzed using Weibull statistics. It was found that the effect of in-plane residual stresses on crack formation in the laminate depends on the disposition of the compressive spinel layers, either at the surface or embedded in the structure. Embedding alumina between spinel layers increased the load-bearing capability before crack initiation by similar to 70 % compared to spinel, offering a promising approach to enhance contact damage resistance.The brittle response of transparent spinel ceramics to contact damage is limiting their application as an alternative to glasses and single crystals. In this work, we explore a strategy to enhance the contact damage resistance of spinel ceramics by embedding alumina layers in a multi-layer architecture. Crack initiation upon Hertzian indentation was investigated in MgAl2O4 - Al2O3 laminates and compared to their corresponding monoliths. Contact stresses during loading were analyzed using finite element simulations by considering the elastic properties of the layers and contact non-linearities. Results were analyzed using Weibull statistics. It was found that the effect of in-plane residual stresses on crack formation in the laminate depends on the disposition of the compressive spinel layers, either at the surface or embedded in the structure. Embedding alumina between spinel layers increased the load-bearing capability before crack initiation by similar to 70 % compared to spinel, offering a promising approach to enhance contact damage resistance.