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In-Situ Fracture Tests Of Brittle Materials At The Microscale, Giorgio Sernicola, Giovannini Tommaso, Rui Hao, T. Ben Britton, Finn Giuliani

Nanomechanical Testing in Materials Research and Development V

The fracture toughness of ceramics is often dominated by the structure of their grain boundaries. Our ability to improve life of ceramic components depends on our ability to investigate properties of individual grain boundaries.

This requires development of new fracture testing methods allowing high spatial resolution and high control over the area to test. Further benefits of these ‘small scale’ approaches will enable testing of specimens for which big volumes are not available (e.g. thin films, coating, or simply samples of dimensions limited by production process).

Recently, several techniques have been developed using small scaled mechanical testing, based within a …

Micromechanical Behavior Of Thermal Barrier Coatings After Isothermal Oxidation, Carlos Serna, Deiby Maya, Alejandro Toro, Juan Meza

Nanomechanical Testing in Materials Research and Development V

Thermal protection of metallic components by using ceramic coatings like thermal barrier coatings (TBCs) is widely used, in rocket engines, aircraft industry and gas turbines for power generation to reduce the substrate temperature up to 165°C. This technology diminishes the heat transfer in combustor, initial rotor blades and nozzles guide vanes, so that turbines have taken special advantage of these coatings to meet increasing demands for greater fuel efficiency, lower NOx emissions and higher power and thrust [1]. Thermal barrier coatings, apart from thermal protection are also used to protect against abrasion, oxidation and corrosion [2].

The understanding of the …

Fracture Behavior Of High Strength Pearlitic Steel Wires, Bernhard Voelker, Anton Hohenwarter, Reinhard Pippan

Nanomechanical Testing in Materials Research and Development V

Steel wires are widely used in various industrial applications. Hence, the drawing process and the resulting mechanical properties are of significant scientific and industrial importance. In this investigation the focus is on pearlitic steel wires with relatively high drawing strains and resulting high ultimate tensile strengths up to several GPa.

The fracture behavior was investigated for two different wires with a drawing strain of 3.10 and 6.52 with a diameter of about 100 µm and 20 µm, respectively. The resulting ultimate tensile strength varies between 4 and 7 GPa [1]. The fracture toughness was measured with crack propagation direction in …