Tensile Anisotropy of a Single Crystal Superalloy

To investigate the orientation and temperature dependence of the tensile strength in single crystal superalloys, tensile tests were carried out on a single crystal nickel-based superalloy with three orientations of tensile axis: [001], [011] and [111], in the temperature range from 20 to 1100°C. The results indicated that the yield strength and ultimate tensile strength of the alloy got the maximum in [111] orientation at room temperature, reached another peak in [001] orientation at 760 °C, and then decreased dramatically in all three orientations with higher temperature. The relationship between yield strength and temperature well accorded with an Arrhenius-type formula. It revealed the yield deformation mechanisms for the alloy were slip on octahedral planes at room temperature and diffusion-controlled dislocation climb at elevated temperatures.