Nanomechanical properties of a nickel-base single-crystal superalloy up to 700°C

A strong temperature-dependent effect in the range from 25°C to 700°C in the nanomechanical behaviour has been found in a single-crystal nickel-base superalloy. The hardness of this alloy gradually increases from 25°C to 400°C and then rapidly decreases, in contrast to the peak tensile yield strength which occurs at around 700°C. The nanomechanical response is strongly dependent on the indentation load over a wide range of temperature, which is rationalised by its unique γ/γ’ dual-phase microstructure. The experimental measurements show that the hardness is position-sensitive owing to its unique solidified dendrite microstructure when the indentation marks span 640 μm.