Influence of temperature on tensile behavior and deformation mechanism of Re-containing single crystal superalloy

Tensile properties of a Re-containing single crystal superalloy were determined within the temperature range from 20 to 1 100 degrees C with a constant strain rate of 1.67x10(-4) s(-1). From room temperature to 600 degrees C, the yield strength increases slightly with increasing temperature. The yield strength decreases to a minimum at 760 degrees C, while a maximum is reached dramatically at 800 degrees C. The elongation and area reduction decrease gradually from room temperature to 800 degrees C. Above 800 degrees C, the yield strength decreases significantly with increasing temperature. The gamma' phase is sheared by antiphase boundary (APB) below 600 degrees C, while elongated SSF (superlattice stacking fault) is left in gamma' as debris. At 760 degrees C the gamma' phase is sheared by a/3 < 112 > superpartial dislocation, which causes decrease of yield strength due to low energy of SSF. Above 800 degrees C, dislocations overcome gamma' through by-passing mechanism.