Abstract:Tensile properties of a Re-containing single crystal superalloy were determined within the temperature range from 20 to  1 100 °C with a constant strain rate of 1.67´10⁻⁴ s⁻¹. From room temperature to 600 °C, the yield strength increases slightly with increasing temperature. The yield strength decreases to a minimum at 760 °C, while a maximum is reached dramatically at 800 °C. The elongation and area reduction decrease gradually from room temperature to 800 °C. Above 800 °C, the yield strength decreases significantly with increasing temperature. The γ′ phase is sheared by antiphase boundary (APB) below 600 °C, while elongated SSF (superlattice stacking fault) is left in γ′ as debris. At 760 °C the γ′ phase is sheared by a/3á112ñ superpartial dislocation, which causes decrease of yield strength due to low energy of SSF. Above 800 °C, dislocations overcome γ′ through by-passing mechanism.

Key words: single crystal superalloy; tensile behavior; yield strength; microstructure