Nanoindentation is an attractive characterization technique, as it not only measures the local properties of a material but also facilitates understanding of deformation mechanisms at submicron scales. However, because of the complex stress-strain field and the small scale of the deformation under the nanoindenter, the results can be easily influenced by artifacts induced during sample preparation. In this work, a systematic study was conducted to better understand the influence of sample preparation methods on the nanoindentation results of ductile metals. All experiments were conducted on a steel (Fe-22Mn-0.65C, wt%) with twinning-induced plasticity (TWIP), which was selected for its large grain size and sensitivity to different surface preparation methods. By grouping the results obtained from each nanoindent, chemical polishing was found to be the best sample preparation method with respect to the resulting mechanical properties of the material. In contrast, the presence of a deformation layer left by mechanical polishing and surface damage induced by focused ion beam (FIB) scanning were confirmed by the dislocation-nucleation-induced pop-in events of nanoindentation.

纳米压痕是一种有吸引力的表征技术，因为它不仅可以测量材料的局部特性，而且可以帮助理解亚微米尺度的变形机理。但是，由于复杂的应力应变场和纳米压头下的小规模变形，结果很容易受到样品制备过程中产生的伪影的影响。在这项工作中，进行了系统的研究，以更好地理解样品制备方法对韧性金属纳米压痕结果的影响。所有实验均在具有孪生诱导塑性（TWIP）的钢（Fe-22Mn-0.65C，wt％）上进行，该钢因其大晶粒尺寸和对不同表面制备方法的敏感性而被选择。通过对从每个纳米压痕获得的结果进行分组，就所得材料的机械性能而言，发现化学抛光是最好的样品制备方法。相反，通过位错成核诱导的纳米压痕事件证实了机械抛光留下的变形层和聚焦离子束（FIB）扫描引起的表面损伤。