Physicomechanical properties of ultrahigh temperature heteromodulus ceramics based on group 4 transition metal carbides

Abstract

Highly densified TiC, ZrC and HfC based ultrahigh temperature heteromodulus ceramics (HMC), containing 10-50 vol.-% of low modulus phase in the form of particulate graphite, were prepared by hot pressing at 2700uC and 12 MPa in argon atmosphere. The microstructure, elastic characteristics, flexural and compressive static strength, fracture toughness, impact resistance, hardness and thermal expansion were investigated and compared with those available in earlier works for clear understanding the composition-property correlations and anisotropy of this type of HMC composites. Different thermal shock resistant parameters for the HMC were calculated on the basis of obtained experimental data. A new principle of optimum materials design for the compositions in the refractory carbide-graphite systems is exemplified by the TiC-C HMC materials.

Fracture toughness in some hetero-modulus composite carbides: carbon inclusions and voids

“…Sintered composite hardness (a) and fracture toughness (b). Mechanical properties of boron and titanium carbides (data for points at TiC concentration 0 and 100 at.-%) are in accordance with[14,15,31,32].…”

Mechanisms of TiB2 and graphite nucleation during TiC–B4C high temperature interaction

“…Presence of graphite or hexagonal boron nitride phases in superhard and refractory carbides, nitrides and borides result in substantial increase of thermal shock resistance [1][2][3], and machinability [4][5][6], with no impediment of high temperature properties. Some penalty, associated with the soft phases to hardness and strength are considered to be a "fair price" for other gains.…”

Physical and mechanical properties of the hotpressed ZrB₂‒TaC‒SiC materials

“…ВВЕДЕНИЕ В разработке новых сверхвысокотемпературных керамик (Ultra-High Temperature Ceramics -UHTCs) в последние годы наблюдается тенденция к усложнению их фазового и химического состава, созданию многокомпонетных материалов с участием тугоплавких боридов, карбидов, силицидов, нитридов переходных металлов, а также ковалентных соединений (SiC, B 4 C, Si 3 N 4 ) [1][2][3][4][5][6][7][8][9][10][11]. Это связано с тем, что возможности дальнейшего улучшения высокотемпературных свойств (стойкости к окислению, теплопроводности, термостойкости и др.)…”