Micro- and macro-mechanical testing of transparent MgAl2O4 spinel
- 457 Downloads
Advanced transparent ceramics with high chemical and thermal stability are gaining increasing interest as replacement of glass-based materials in technical window applications. The mechanical reliability and performance of transparent MgAl2O4 with a grain size of 5 μm has been characterized at ambient temperature using micro-mechanical indentation and macroscopic bending tests. The measurements focused on elastic modulus, fracture toughness, crack kinetics, and strength, the latter analyzed with Weibull statistics. The effect of slow crack growth is assessed using a strength–probability–time plot. Complementary fractography by optical, confocal and scanning electron microscopy provided a correlation between failure origin and fracture stress. The results and reliability aspects are discussed in terms of linear elastic fracture mechanics.
The study was financially supported by the German Federal State of Northrhine Westfalia (Project TRANAK: Transparente Nano Keramik). The authors would like to express their gratitude to J. Mönch, T. Osipova, R. Küppers (IEK-2), and H. Menges (IEK-1) for their experimental support and Dr. E. Wessel (IEK-2) for the SEM investigations.
- 15.Choi SR, Salem JA, Holland FA (1997) Estimation of slow crack growth parameters for constant stress-rate test data of advanced ceramics and glass by the individual data and arithmetic mean methods, NASA Technical Memorandum 107369Google Scholar
- 17.Barsoum MW (1996) Fundamentals of ceramics. McGraw-Hill, New YorkGoogle Scholar
- 21.Quinn GD (2007) Guide to practice for fractography of ceramics and glasses, NIST Special Publication SP 960-16Google Scholar