@article{oai:kitami-it.repo.nii.ac.jp:00007161,
 author = {YAN, Jiwang and MAEKAWA, Kouki and TAMAKI, Jun-ichi and KUBO, Akihiko},
 issue = {1},
 journal = {JSME International Journal Series C},
 month = {Jan},
 note = {Single-crystal germanium is an important infrared optical material. In the present work, single-point diamond turning experiments on single-crystal germanium （100）, （110） and（111） planes were conducted in order to examine their ultraprecision machining characteristics. Three kinds of surface textures and chip morphologies were observed during the brittle-ductile transition of the machining mode. The brittle-ductile boundary changed significantly with the crystal orientations of the workpieces. Due to the crystallographic anisotropy, micro-fractures were generated on the workpiece surface in a radial pattern from the rotation center. However, it was possible to produce completely ductile-cut surfaces on all crystal orientations by using undeformed chip thicknesses smaller than a critical value, namely, the minimum critical undeformed chip thickness, which was approximately 60 nm under the present conditions. Compared to wet cutting, dry cutting was beneficial for ductile machining on a few specific crystal orientations. The findings in this study provide criterions for determining process parameters for the fabrication of aspherical and diffraction infrared optics using single-crystal germanium., application/pdf},
 pages = {29--36},
 title = {Experimental Study on the Ultraprecision Ductile Machinability of Single-Crystal Germanium},
 volume = {47},
 year = {2004}
}