ABSTRACT

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.

摘要

在 25°C 至 700°C 的范围内，单晶镍基高温合金的纳米力学行为具有强烈的温度依赖性效应。这种合金的硬度从 25°C 逐渐增加到 400°C，然后迅速下降，这与在 700°C 左右出现的峰值拉伸屈服强度形成对比。纳米机械响应强烈依赖于在很宽的温度范围内的压痕载荷，这通过其独特的 γ/γ' 双相微观结构来合理化。实验测量表明，当压痕跨度为 640 μm 时，由于其独特的凝固枝晶显微组织，硬度对位置敏感。