TiC–High Mn Steel‐Bonded Cermets with Improved Strength and Impact Toughness

Abstract

TiC–high Mn steel‐bonded cermets are prepared by powder metallurgy techniques. The effects of (Ti0.5W0.5)C or WC on the microstructure, hardness, transverse rupture strength (TRS), and impact toughness (IM) are investigated. The results show that regardless of the additives used, the hardness and TRS of cermets increase with the increase in W content. However, IM is not directly proportional to the W content. Peak IM value is obtained at 5% WC addition. The highest IM of 15.12 J cm−2 is measured from the cermet with (Ti0.5W0.5)C additive with a hardness and TRS of 64.8 HRC and 2510 MPa, respectively. Liquid phase sintering occurs at vacuum sintering. Black core–gray outer rim structure is formed in cermets with WC additives and white inner rims appear in cermets with higher W content. White core–gray rim structure is formed in cermets with (Ti0.5W0.5)C additives. The impact fracture mode of the cermets is the intergranular fracture accompanied by the tearing edges of the binder. The tearing of the high Mn steel binder is the main source of IM. IM peaks are attributed to the contradictory effects of decreased fraction and refined binder microstructure.

Effect of TiCp volume fraction and WCp addition on the mechanical properties of TiCp/Cr8Mo2VSi composites

“…As can be seen from the figure, there is a thin layer of elemental W around the ceramic particles and the rest of elemental W is dispersed into the matrix. The ceramics with added WCp form a black core-white inner edge-grey outer edge structure through a dissolution-reprecipitation mechanism [20]. A part of WCp is encapsulated in the edges of the ceramic particles to form a heart-edge structure, which improves the elastic modulus of the TiC ceramic particles and contributes to the improvement of the composite's impact fracture resistance.…”

“…Li et al [20] used powder metallurgy technology to prepare TiC reinforced high manganese steel matrix composites. They investigated the effect of WC addition on the composites' hardness, transverse fracture strength, and impact toughness.…”

“…The resulting TiC-reinforced steel-matrix composites exhibit high hardness, wear resistance, chemical stability, and thermal conductivity [18,19]. Li et al [20] prepared high manganese steel matrix composites reinforced with TiC using a powder metallurgy process. They investigated the effect of WC on the properties of the composites and found that the WC particles formed a heart-edge structure around the TiC particles.…”

In-situ alloying of TiC-FeCr cermets in manganese vapour

“…This, coupled with the fact that FeMn alloys are less expensive, relatively abundant and non-toxic, makes them promising candidates for replacing Co-and Ni-based binder systems in ceramicmetallic composites (hardmetals and cermets). There have been attempts to develop wear resistant high-manganese WC-FeMn or WC-FeCrMn hardmetals [5][6][7][8][9][10][11][12] and W-free TiC-FeMn or TiC-FeCrMn [13][14][15][16][17][18][19][20][21] cermets. However, only few studies have directed attention to the fact that due to its high vapour pressure Mn is highly volatile at higher temperatures causing severe Mn loss through sublimation evaporation during vacuum sintering [6-9, 12,20,21].…”