Comprehensive study on material behaviors in nanometer machining of brittle materials and its applications

脆性材料纳米加工材料行为综合研究及其应用

基本信息

批准号：
06302035
负责人：
SATA Toshio
金额：
$ 12.99万
依托单位：
Toyota Technological Institute
依托单位国家：
日本
项目类别：
Grant-in-Aid for Co-operative Research (A)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

项目摘要

To understand the mechanisms of ductile mode material removal at small depth of cut and the transition in material removal from brittle to ductile in machining of brittle materials, experimental studies on micromachining of various brittle materials and molecular dynamics (MD) computer simulations on microcutting of defect free monocrystalline silicon are carried out.Mophological observations of worksurfaces machined by diamond turning and ELID griding under various machining conditions by optical microscope, SEM and AFM show that any brittle material, regardless of their intrinsic brittleness, can be machined in pure ductile mode under a sufficiently small size of unit process (corresponding to uncut chip thickness in turning, grain depth of cut in grinding). Usefulness of microindentation testing and single point scratch testing with continuously increasing of depth of cut is demonstrated for the evaluation of intrinsic brittleness or ductility and critical size of unit process for d … More uctile mode machining of individual materials.MD simulations suggest that the critical depth of cut can be governed by the amount of energy of elastic waves generated in cutting zone as the results of release of potential energy stored in workpiece by the plowing of cutting edge. "Renormalized MD" simulation, in which the concept of "renormalization" is combined with conventional MD simulation, is proposed so that MD can be applied to various size of unit proces ranging from nanometer to micrometer scale. The results of renormalized MD simulations on microcutting of silicon under the uncut chip thickness from 1 nm to 1 mm show that chip removal is performed in ductile mode even at 1 mm uncut chip thickness. However, by incorporating the effect of chemical adsorption of atomospheric gas and/or liquid on cutting tool and workpiece, which was not considered in conventional MD simulation, the brittle-ductile transition phenomena can be observed. The result suggests that there must be some additional mechanism such as chemical adsorption of atomospheric gas and/or liquid in brittle-ductile transition in material removal process of brite materials. Less

为了了解脆性材料加工中小切深延性模式材料去除的机制以及材料去除从脆性到延性的转变，对各种脆性材料进行微加工实验研究和缺陷微切削的分子动力学（MD）计算机模拟利用光学显微镜、SEM 和 AFM 对金刚石车削和 ELID 网格在不同加工条件下加工的工作表面进行形貌观察，结果表明：脆性材料，无论其固有的脆性如何，都可以在足够小的单元工艺尺寸下以纯延性模式进行加工（对应于车削中的未切削切屑厚度、磨削中的切削晶粒深度）。随着切削深度的不断增加，可用于评估固有脆性或延展性以及单个材料的延性模式加工的单元工艺的临界尺寸。MD 模拟表明，临界深度切削量可以通过切削刃切削释放工件中储存的势能而在切削区域产生的弹性波能量来控制，其中“重整化”的概念是。结合传统的MD模拟，提出MD可以应用于从纳米到微米尺度的各种尺寸的单元工艺。对未切割芯片厚度从1 nm到1 mm的硅微切削进行重正化MD模拟的结果表明：即使在未切屑厚度为 1 mm 的情况下，也可以以延性模式进行切屑去除。然而，通过考虑大气气体和/或液体对切削刀具和工件的化学吸附作用，这在传统 MD 模拟中没有考虑到。结果表明，在脆性材料的材料去除过程中，一定存在一些额外的机制，例如大气气体和/或液体的化学吸附。