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通过对不同结构的高纯钨进行微米和纳米压痕实验,发现压痕尺寸和晶粒/亚晶粒尺寸对材料的硬度有重要影响。探讨硬度的晶界效应和压痕尺寸效应。采用Nix-Gao模型,结合尺度因子对实验获得的压痕硬度值进行拟合。结果表明,尺度因子几乎与晶粒或亚晶粒的尺寸无关。塑性变形区与晶界或亚晶界之间的相互作用是导致硬度在某一特定深度增加的原因,而塑性变形区与晶粒或亚晶粒的尺寸几乎无关。当塑性变形区扩展增大到单个晶粒或亚晶粒尺寸时,压痕硬度开始趋于稳定。
Through the experiments of different structure of high purity tungsten in indentation and nanoindentation, it is found that indentation size and grain / subgrain size have an important influence on the hardness of the material. The effects of grain boundary effect and indentation size on hardness are discussed. The Nix-Gao model and the scale factor were used to fit the indentation hardness values obtained from the experiment. The results show that the scale factor is almost independent of the size of the grains or subgrains. The interaction between the plastic deformation zone and the grain or subgrain is responsible for the increase in hardness at a certain depth, whereas the plastic deformation zone has little to do with the grain or subgrain size. As the plastic deformation zone expands to a single grain or subgrain size, the indentation hardness begins to stabilize.