Mechanical heterogeneity in rocks with a nano-indentation tester

采用金字塔形金刚石压头的纳米压痕测试仪（RIDER-1）可以高精度地测量加载和卸载周期内的载荷和位移。在室温一大气压下，对天然石英进行了负载为98 mN的维氏压痕试验。原子力显微镜显示在压痕过程中没有断裂的迹象。透射电镜观察表明，在压痕试验中没有产生位错。然而，高分辨率电子显微镜显示，晶体晶格已经形成了尖锐的折痕。这些观察得出石英即使在室温下也具有塑性变形的结论。塑性应变是由晶格折痕机制调节的，本文首次对这一机制进行了描述。用Oliver-Pharr法测定石英、长山石和蓝帘石的杨氏模量，分别为14.7、37.1和46 GPa。

A nano-indentation tester (RIDER-1) with a pyramidal diamond indenter can measure the load and the displacement with a high precision during the loading and unlaoding cycle. Vickers indentation test of natural quartz were performed with a load of 98 mN at room temperature and one atmosphere. Atomic force microscopy revealed no evidence of fracturing during indentation. Transmission electron microscope observations indicate that no dislocations were generated during the indentation tests. However, high resolution electron microscopy revealed that sharp creases of crystal lattices had developed. These observations lead to the conclusion that quartz deformed plastically even at room temperature. The plastic strain was accommodated by the mechanism of lattice creasing, which is described here for the first time. Young's modulus of quartz, piedmontite and glaucophane were also measured with the Oliver-Pharr method, the results being 14.7, 37.1 and 46 GPa, respectively.