Papers by Keyword: Critical Ductile Grinding Depth

Abstract: The brittleness, plasticity, super-plasticity and the removal mechanisms of critical fragmentation of the nano ZrO2 ceramics were investigated. The formula of critical ductile grinding depth of the common engineering ceramics was inapplicable to the nano-ZrO2 ceramics. A new formula of critical ductile grinding depth of the nano ceramics was established. The ultrasonic vibration grinding experiments showed that the critical ductile grinding depth of the ceramics was 15μm by conventional grinding, but the increment of the critical ductile grinding depth was 60 percent by ultrasonic grinding. The critical ductile grinding depth increased to 25μm. Analyzed by means of SEM, it was transgranular cracking during its cracking process. The nano-ZrO2 ceramics have high toughness so the critical ductile grinding depth increased. The shape, length, width and thickness of the grindings differed greatly from which obtained by conventional grinding.

Abstract: Nano ceramics possesses excellent mechanical property and physical characteristics in contrast to conventional engineering ceramics, so it has tremendous application prospect. Adopting ultrasonic composite processing we describe the influences of grinding speed, grinding depth, wheel granularity and no-spark grinding times on the surface roughness of nano ZrO2 ceramics. By means of SEM and AFM the surface character and critical ductile grinding depth of nano ZrO2 ceramics in the condition of conventional and ultrasonic grinding are also discussed. At last, the residual stress of surface and crystalline phase transformation under the condition of conventional grinding and ultrasonic vibration grinding were analyzed by X-ray diffraction. The research indicated that ultrasonic vibration grinding could obtain nano finished surface with high efficiency. The residual stress of nano ZrO2 ceramics surface is determined much by different grinding styles.

Abstract: The crack extension course and ductile removal mechanism of nano ZrO2 ceramics were analyzed in this paper. On the basis of contrast tests with or without ultrasonic vibration, the influences of critical ductile grinding depth on grinding forces and surface quality were studied by dynamometer, SEM and AFM in different grinding condition. The reason for the increase of the critical grinding depth was discussed based on the analysis of grinding force and ultrasonic vibration course. At last, the formation mechanism of surface topography observed by AFM in ductile domain was analyzed. The research indicated that ultrasonic machining could obtain nano finished surface with high efficient.

Abstract: Nano ceramics possessed ascendant mechanical property and physical characteristics contrast with engineering ceramics, so it has extensive application prospect in various industries. On the basis of applying the indentation fracture mechanics to analyze the removal mechanics of ceramic material, this paper analyzed the critical ductile grinding depth of the nano ZrO2 ceramics. Adopting ultrasonic composite processing we describe the influence of different processing parameters and grain size of diamond wheel on the grinding forces and surface roughness. Based on the grinding forces and surface roughness the grinding process with and without vibration is analyzed. By means of SEM and AFM the surface character and critical ductile grinding depth of nano ZrO2 ceramics are also discussed. The paper supplied the theoretical and experimental basis for the grinding of the large-sized ultraprecision plate structure of nano ZrO2 ceramics (nm).