10:00 AM - 11:00 AM
Amit Shyam, Materials Science and Technology Division, Oak Ridge Materials and Chemistry Seminar Series
Email: Adrian SabauPhone:
Porous microcracked ceramics have emerged as important technical materials on which devices such as diesel particulate filters are based. In recent years, as research and development of this class of materials has intensified, it is now apparent that these materials have unusual thermomechanical properties that go along with their functional properties. Examples of unusual mechanical properties such as non-linear tensile behavior and Young’s modulus increase with temperature will be highlighted for common systems namely cordierite (Mg2Al4Si5O18), β-eucryptite (LiAlSiO4) and aluminum titanate (Al2TiO5). The unusual mechanical properties can in many cases be attributed to a grain-scaled fracture phenomenon that is termed microcracking. Microcracking results from thermal mismatch in the microstructure (at the lattice level or between different phases) and the density of microcracks in the material may evolve with loading and/or temperature change. The effect of microcracking on the thermal expansion, Young’s modulus, tensile behavior, microscopic internal stresses and macro- scale fracture mechanisms will be highlighted with the help of appropriate examples.
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