C.Z. Huang

A study on the prediction of the mechanical properties of a ceramic tool based on an artificial neural network

Abstract A new type of ceramic tool material is usually developed with the “trial-and-error” method which wastes a lot of time and effort. With the advancement of computers and ceramic material science, ceramic material design can be carried out based on known knowledge and experience of the fabricated materials, with the aid of the computer. The compositions and contents of the ceramic tool materials to be developed may be designed and simulated in accordance with the requirement for the mechanical properties. The development process of a new ceramic tool material can be carried out based on the simulated information of the material composition and content. In this paper, the characteristics of the artificial neural network (ANN) and it’s applications in the design of ceramic tool materials are introduced. The non-linear mapping relationship between the component, the composition content of raw material, the flexural strength, and the fracture toughness of the composite ceramic tool is investigated. The model for predicting the mechanical properties of the alumina matrix ceramic tool is established by means of an ANN. On the basis of the neural network toolbox in MATLAB (MATrix LABoratoryMA software), the neural network model for predicting the mechanical properties of the ceramic tool is trained to be reliable and the required programs are compiled. The mechanical properties of two-phase and three-phase composite ceramic tools such as Al 2 O 3 –(W, Ti)C and Al 2 O 3 –TiC–ZrO 2 are predicted to verify the proposed model. It is found from the research results that the established model based on the ANN are available and effective in simulating the composition content and predicting the mechanical properties of the ceramic tool.

Erosion mechanisms of monocrystalline silicon under a microparticle laden air jet

Microabrasive air-jet machining is considered as a promising precision processing technology for silicon substrates. In this paper, the impressions produced on a monocrystalline silicon by the impacts of microsolid particles entrained by an air jet and the associated microscopic erosion mechanisms are presented and discussed. It is shown that the impressions can be classified into three categories, namely, craters, scratches, and microdents, of which two types of craters and two types of scratches can lead to large-scale fractures. Craters with cleavage fracture surfaces have been found to play an important role in the material removal process. In addition, it is shown that most particles bounced away from the target surface without sliding or rolling during an impact so that most impressions formed are crater-type erosions.

Abrasive liquid jet as a flexible polishing tool

As a flexible polishing technology, abrasive jet using water or other liquids as the flow medium (and hence called abrasive liquid jet) has been used for deburring and polishing applications. It has the advantage of polishing on various complex curved surfaces without the need for special tooling. This paper presents an overview of the principles of the abrasive liquid jet polishing technology and the polishing mechanisms, followed by the analysis of the polishing performance. The simulation and modelling studies for the abrasive liquid jet polishing process are then discussed. Finally, the future research and application trends of this polishing technology are given.

A study on the development of a composite ceramic tool ZrO2/(W, Ti)C and its cutting performance

Abstract An experimental investigation is carried out to fabricate a new ceramic tool ZrO2/(W, Ti)C by the hot pressing method and to study the effects of (W, Ti)C on the microphotograph of crystal particles, the phase transition and the mechanical properties of the new ceramic tool. Scanning electron microscope (SEM) observation reveals that the densification degree of the material ZrO2/(W, Ti)C may be improved and that the microstructure of the new ceramic tool material is more homogeneous as a result of the proper addition of the powder (W, Ti)C. Tests of the mechanical properties and wear resistance in machining are conducted. It is found that the fracture toughness of the developed ceramic tool is the highest when the content of powder (W, Ti)C is 45% in terms of volume due to the highest content of tetragonal zirconia. It is also shown that when machining a carbon tool steel the new tool material can increase the tool-life as compared to other ceramic tool materials that have the same matrix but were fabricated without (W, Ti)C, while the fracture toughness is improved by up to 38.8%. When compared with a conventional ceramic tool, the new ceramic tool material exhibit superior ability in maintaining wear resistance during the entire tool-life.

Study on Mechanical Properties of Multi-Scale and Multi-Phase Nanocomposite Ceramic Tool Materials

The single nano-scale and multi-phase nanocomposite ceramic materials including Al2 O3 /Al2 O3n /SiCn and Al2 O3 /Ti(C0.7 N0.3 )n /SiCn are successfully fabricated. Their mechanical properties are better than those of the single-phase alumina material and conventional alumina matrix materials. The multi-scale and single-phase nanocomposite ceramic tool material Al2 O3 /SiCμ /SiCn is also successfully fabricated. Its flexural strength and fracture toughness is higher than those of single-scale materials Al2 O3 /SiCμ and Al2 O3 /SiCn . The multi-scale and multi-phase nanocomposite ceramic tool material Al2 O3 /TiCμ /TiNn is finally developed by incorporation and dispersion of micro-scale TiC particle and nano-scale TiN particle in alumina matrix, which can get higher flexural strength and fracture toughness than those of Al2 O3 /TiC ceramic tool material without nano-scale TiN particle. The coexistent function of nano-scale Al2 O3 or Ti(C0.7 N0.3 ), nano-scale SiC and TiN can reduce the sintering temperature and sintering duration time as well as the grain size, and improve the material densification and mechanical properties. The nano-scale SiC grains locating along the grain boundary and inside the micro-scale alumina can form the hybria intergranular-intragranular microstructure which can result in hybria intergranular-transgranular fracture and improve the mechanical properties of the ceramic material. Crack deflection, forking and bridging effects are the main cause for improving the fracture toughness of the materials including Al2 O3 /Ti(C0.7 N0.3 )n /SiCn and Al2 O3 /TiCμ /TiNn .Copyright