Публикации за 2018 год

Spark plasma and conventional sintering of ZrO2-TiN composites: A comparative study on the microstructure and mechanical properties

MATEC Web of Conferences(WoS), 2018, Volume 224, Article Number 01055, Page 7

Abstract. Spark plasma sintering (SPS) is an extremely fast solidification technique for compounds that are difficult to sinter within the material group metals, ceramics or composites. SPS uses a uniaxial pressure and a very rapid heating cycle to consolidate these materials. This direct way of heating allows the application of very high heating and cooling rates, enhancing densification over grain growth promoting diffusion mechanisms allowing maintaining the intrinsic properties of nanopowders in their fully dense products. The ZrO2-TiN cermets prepared by SPS processing achieves the enhanced mechanical properties with the hardness of 15.1 GPa and the fracture toughness of 9.1 MPa∙m1/2 in comparison to standard reference ZrO2-TiN material.

SEM images of polished and thermally etched sections of SPS sintered (1300°C (a), 1400°C (b) and 1500°C (c)) ZrO2 composites.

Исполнители: Y. Pristinskiy, W. Solis, A. Smirnov

Дата публикации: 30-10-2018

Источник: https://www.matec-conferences.org/articles/matecconf/abs/2018/83/matecconf_icmtmte2018_01055/matecconf_icmtmte2018_01055.html

The influence of hydrojet surface processing on the adhesive strength of wear-resistant coatings deposited on a metal-cutting tool of oxynitride ceramics

MATEC Web of Conferences(WoS), 2018, Volume 224, Article Number 01066, Page 4

Abstract. The work represents a new approach of preliminary surface treatment of replaceable polyhedral cutting ceramics inserts for significant increase of adhesion strength with deposited wear-resistant nitride ceramics. By this method the hydrojet treatment was used to repair surface defects occurring during manufacturing process of any required geometry of cutting inserts.

Al2O3-TiC tool ceramics surface before (a) and after (b) hydrojet treatment

Исполнители: Seleznev A.E., Smirnov A., Peretyagin P.Yu.

Дата публикации: 30-10-2018

Источник: https://www.matec-conferences.org/articles/matecconf/abs/2018/83/matecconf_icmtmte2018_01066/matecconf_icmtmte2018_01066.html

Wire electrical discharge machining of 3Y-TZP/Ta ceramic-metal composites

Journal of Alloys and Compounds(WoS, Q1, IF=3,779), 2018, Volume 739, Pages 62-68

 

Abstract. Dense (>98 th%) and homogeneous ceramic/metal composites were obtained by spark plasma sintering (SPS) using ZrO2 and lamellar metallic powder of tantalum (20 vol%) as starting materials. Composites showed a fracture toughness value of 16 MPa m1/2 mainly due to crack bridging of the elastic–plastic deformations of ductile metal particles. This fracture toughness was accompanied by a simultaneous enhancement in damage tolerance and fatigue resistance of 3Y-TZP/Ta composites.

Besides exceptional mechanical properties, SPS sintered 3Y-TZP/Ta composites also showed the electrical conductivity suited to wire electrical discharge machining (WEDM). Therefore, they are suitable to be produced in mechanically performant, complex shape components with the required tolerance while reducing machining costs. The aim of this work was the study of the electrical properties of the materials as well as the characteristics of the machining process and the machined surfaces influence on the bending strength of composites. The results show that workpieces can be machined with high accuracy and without a drop in mechanical strength.

Keywords. Ceramic-metal composites; Spark plasma sintering (SPS); Wire electrical discharge machining (WEDM); Surface roughness

SEM micrographs of a polished (A) and a fractured (B) surface of 3Y-TZP/Ta composite. Zirconia: dark-gray; tantalum: light-gray inclusions. White arrows show decohesion between the matrix and the metallic particles. Yellow arrows show plastic deformation of Ta.

Исполнители: A. Smirnov, P. Peretyagin, J.F. Bartolome

Дата публикации: 30-03-2018

Источник: https://www.sciencedirect.com/science/article/pii/S0925838817344171?via%3Dihub