Microtwinning avalanches induced the Protevin–Le Châtelier effect in PWA1483 at 750 °C

Abstract

The flow behavior and deformation mechanisms of the [001]-oriented single-crystal nickel-based superalloy PWA1483 are investigated under quasi-static compressive and tensile loading conditions at 750°C. We found that the tensile yield strength is larger as compared to the compressive strength, and the serrated flow only appears on the compressive stress–strain curves. Microstructural observations uncover that stacking fault shearing and microtwinning are prone to initiate in PWA1483 during tensile deformation, and the appearance of the Protevin–Le Châtelier effect in compression derives from the abrupt frequent bursts of the two mechanisms on a mesoscale, rather than the simple occurrence of these procedures.

Keywords

• Nickel-based superalloy
• Protevin–Le Châtelier effect
• tension/compression asymmetry
• stacking faults
• microtwins