Abstract
AbstractThermal strength for anisotropic bodies is considered in case of single-crystal nickel alloys widely used in manufacturing of high-temperature gas turbine blades. Anisotropy of mechanical properties and failure conditions, typical for single crystals, is described. Experimental data for deformation and damage of single-crystal specimens under extension are compared with results of theoretical predictions. The role of the «Schmid factor» describing the relative level of tangential stresses in different slip systems is discussed. It is shown that its maximum value corresponds to a critical stress state related to the initiation of plastic deformation or material damage only for specimen extension and cannot be considered as a failure criterion of a single-crystal body for other loading orientations. Comparison of calculated maximal tangential stresses, with their critical values, obtained by testing specimens of chosen orientation under appropriate loading gives better results. It is demonstrated that strength analysis of single-crystal machine parts under combined stresses may rely on material properties associated with uniaxial loading at a certain “equivalent” specimen orientation. Several problems of creep, low and high cyclic fatigue, and thermal fatigue of anisotropic bodies are also discussed.KeywordsSlip SystemTangential StressFatigue LimitThermal FatigueHigh Cyclic FatigueThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.
Published Version
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