The creep behavior of pure nanocrystalline (nc) fcc metals has not been studied above 200 °C because the nanoscale grains tend to grow at temperatures moderately above ambient. In this work, we study the creep of nanocrystalline Ni–W (nc Ni–W) up to 450 °C, near its thermal stability limit. A nanoindenter with the capability to heat both the specimen and the indenter tip addresses the issue of heat flow and provides more accurate test temperatures when compared to heating only the specimen. Creep experiments are performed on a nc Ni–W film (grain size ∼15 nm) at 300, 350, 400 and 450 °C using the constant load and hold (CLH) method combined with the constant stiffness measurement (CSM) technique in which the peak load is maintained at a constant level. No grain growth occurs even at the highest temperature and highest stress. We conduct an analysis that accounts for the effect of the oscillating loads used in this combined CLH-CSM technique on creep. We find that nc Ni–W exhibits negligible creep at 300 °C, and that at 350 °C, creep in nc Ni–W is three orders of magnitude smaller than creep in pure nc Ni at 100 °C. The creep response of nc Ni–W differs significantly from that predicted by the standard Coble creep model and is attributed to the dislocation–grain boundary interaction.

尚未对200℃以上的纯纳米晶体（nc）fcc金属的蠕变行为进行研究，因为纳米级晶粒倾向于在适度高于环境温度的温度下生长。在这项工作中，我们研究了高达450°C（接近其热稳定性极限）的纳米晶Ni–W（nc Ni–W）的蠕变。与仅加热样品相比，具有同时加热样品和压头尖端的能力的纳米压头解决了热流问题，并提供了更准确的测试温度。使用恒定载荷保持（CLH）方法和恒定刚度测量（CSM）技术，在300、350、400和450°C的nc Ni–W薄膜（晶粒尺寸约为15 nm）上进行蠕变实验。在高峰负载保持在恒定水平。即使在最高温度和最高应力下也不会发生晶粒长大。我们进行了一项分析，该分析考虑了此CLH-CSM组合技术中使用的振荡载荷对蠕变的影响。我们发现nc Ni–W在300°C时的蠕变可忽略不计，而在350°C时，nc Ni–W的蠕变比纯nc Ni在100°C时的蠕变小三个数量级。nc Ni–W的蠕变响应与标准Coble蠕变模型所预测的显着不同，并且归因于位错-晶界相互作用。