Papers by Author: Sui Lian Wang

Abstract: Advanced Ti(C, N) matrix cermet tool materials with higher mechanical properties are successfully developed by dispersing nano-scale Al2O3 powder into the micro-scale Ti(C, N) matrix and Ni-Mo bonding phases powder. The effect of the content of nano-scale alumina on the microstructure and mechanical properties of micro-scale Ti(C, N) matrix cermet tool materials are investigated. The research results show that a type of Ti(C, N) matrix cermet tool material has the most optimal flexural strength of 900MPa, Vickers hardness of 17.4GPa and fracture toughness of 9.95MPa.m1/2 when the content of nano-scale alumina is 12% in term of mass. It is found from the microstructure analysis that the main reason of the mechanical properties improvement is the grain fining effect caused by nano-scale Al2O3.

Abstract: The effect of sintering temperature on mechanical properties and microstructure of rare earth oxides toughened Ti(C,N) ceramic cutting tool materials was investigated. The results showed that the mechanical properties of Ti(C,N) based ceramics were greatly influenced by sintering temperature. As a result, both of the density and mechanical properties of the materials sintered at 1350
and 1400
are worse than those sintered at 1450
and 1500
. Low sintering temperature results in low density and degraded mechanical properties, but too high sintering temperature results in the precipitation of bond metal and thus reduces its fracture toughness. Intergranular fracture mode of the material is mainly observed.

Abstract: The employment of ceramic material simulation design methods can eliminate the disadvantage of traditional ceramic material developing methods of being time-consuming, laborious and high cost. Three simulation methods of artificial neural network, regression analysis and pattern recognition, and their application to ceramic material simulation design were presented in this paper. The problems existing in ceramic material simulation were proposed finally.

Abstract: Ti(C, N) based ceramic tool materials in the Ti (C0.7N0.3)-(Ni-Co)-Cr3C2-VC system have been made by hot-pressing technology, their mechanical properties and fracture morphologies have been studied under three different fabrication conditions. The results show that the mechanical properties are significantly influenced by fabrication conditions, and the main fracture mode is intergranular fracture.

Abstract: In this paper, 3mol% yttria-stabilized tetragonal zirconia polycrystal (3Y-TZP) and TiN/3Y-TZP(adding TiN particles to 3Y-TZP) composites were fabricated by hot-pressing technique. Phase composition, microstructure and mechanical properties of the composites were investigated. It is shown that the flexural strength, fracture toughness and Vickers hardness of TiN/3Y-TZP was significantly improved by the addition of TiN particles compared with 3Y-TZP. The flexural strength of ZYT2 (20wt% TiN addition) is 1318 MPa. The fracture toughness of ZYT4 (40wt% TiN addition) is 16.8MPa·m1/2. The toughening and strengthening mechanisms were analyzed. The XRD results show that the additing of TiN can hinder the transformation from tetragonal phase to monoclinic phase of 3Y-TZP during fabrication process.

Abstract: Nano-scale ceramic materials are very suitable to be used as the high speed cutting tool owing to their excellent properties. The incorporation of nano-scale second phase, such as SiC and Ti(CxN1-x) particles, into a ceramic matrix can lead to an improvement in mechanical properties, which is contributed to a change in microstructure. However, the differences between nano-scale ceramic materials and monoclinic ceramic materials can be found through fabricating these two kinds of materials. Firstly the changes in microstructure that will affect the mechanical properties of the nano-scale ceramic materials are investigated as the nano-ceramic tools are compared with the monolithic ceramic tools. Secondly the effect of microstructure on the mechanical properties is discussed. Finally the microstructure formation mechanism of nano-ceramic materials is given on the bases of some hypotheses.