Lin Wangpiao, Yano Naohiko, Shimizu Jun, Zhou Libo, Onuki Teppei, Ojima Hirotaka
Graduate School of Science and Engineering, Ibaraki University, 4-12-1 Nakanarusawa-cho, Hitachi-shi, Ibaraki 316-8511, Japan.
Department of Mechanical Systems Engineering, Ibaraki University, 4-12-1 Nakanarusawa-cho, Hitachi-shi, Ibaraki 316-8511, Japan.
Nanomaterials (Basel). 2021 Jul 1;11(7):1739. doi: 10.3390/nano11071739.
In this study, single groove nanoscratch experiments using a friction force microscope (FFM) with a monocrystalline diamond tip were conducted on a c-plane sapphire wafer to analyze the ductile-regime removal and deformation mechanism including the anisotropy. Various characteristics, such as scratch force, depth, and specific energy for each representative scratch direction on the c-plane of sapphire, were manifested by the FFM, and the results of the specific scratch energy showed a trend of six-fold symmetry on taking lower values than those of the other scratch directions when the scratch directions correspond to the basal slip directions as 0001⟨112¯0⟩. Since this can be due to the effect of most probably basal slip or less probably basal twinning on the c-plane, a molecular dynamics (MD) simulation of zinc, which is one of the hexagonal close-packed (hcp) crystals with similar slip/twining systems, was attempted to clarify the phenomena. The comparison results between the nanoscratch experiment and the MD simulation revealed that both the specific scratch energy and the burr height were minimized when scratched in the direction of the basal slip. Therefore, it was found that both the machining efficiency and the accuracy could be improved by scratching in the direction of the basal slip in the single groove nanoscratch of c-plane sapphire.
在本研究中，使用带有单晶金刚石尖端的摩擦力显微镜（FFM）在c面蓝宝石晶片上进行了单槽纳米划痕实验，以分析包括各向异性在内的延性区域去除和变形机制。FFM显示了蓝宝石c面上每个代表性划痕方向的各种特性，如划痕力、深度和比能，并且当划痕方向对应于基面滑移方向为0001⟨112¯0⟩时，比划痕能的结果呈现出六重对称趋势，其值低于其他划痕方向。由于这很可能是由于基面滑移或不太可能的基面孪晶在c面上的作用，因此尝试对锌进行分子动力学（MD）模拟，锌是具有相似滑移/孪晶系统的六方密堆积（hcp）晶体之一，以阐明该现象。纳米划痕实验和MD模拟之间的比较结果表明，当沿基面滑移方向划痕时，比划痕能和毛刺高度均最小。因此，发现在c面蓝宝石的单槽纳米划痕中沿基面滑移方向划痕可以提高加工效率和精度。
