A new family of cermets: Chemically complex but microstructurally simple

Abstract

Available online xxxxCermets based on Ti(C,N) have interesting properties, such as high wear resistance, high chemical stability and good mechanical strength at high temperature, but to become a viable alternative to cemented carbides, the fracture toughness and damage tolerance must be significantly improved. Complete solid-solution cermets (CSCs) have been proposed to further improve the mechanical properties of these materials. However, to develop this family of cermets with a high level of quality and reliability, using pre-fabricated complex carbonitrides is necessary instead of unalloyed mixtures as the raw ceramic material. A mechanochemical process called mechanically induced self-sustaining reaction (MSR) is suitable to obtain these complex carbonitrides with high stoichiometric control. On the other hand, high entropy alloys (HEAs), which can also be obtained by mechanochemical processes, are a good candidate to replace the current binder phase in cermets because they exhibit high strength and ductility at high temperature and good resistance to both wear and corrosion. In this work, a new family of CSCs based on (Ti,Ta,Nb)C x N 1−x with HEAs belonging to the Fe-Co-Ni-Cr-Mn-V system as the binder phase is developed by mechanochemical processes. With only two constituent phases, these cermets have a simple microstructure but a high compositional complexity because both the ceramic and binder phases are complex solid solutions with at least five components.

A step forward from high-entropy ceramics to compositionally complex ceramics: a new perspective

“…In addition to two major classes high-entropy UHTCs (discussed above) that have been extensively studied in the last a few years, high-entropy nitrides [67], silicides [44,45], sulfides [98], fluorides [99], aluminides [43], hexaborides [100], carbonitrides [101], and aluminosilicides [38] have been fabricated. In the broader families of oxide-related HECs, the fabrication of high-entropy magnetoplumbites [87,102], zeolitic imidazolate frameworks [103], ferrites [104], phosphates [18,105], monosilicates [19,20], disilicates [106], and metal oxide nanotube arrays [107] have been reported.…”

Production and Properties of High Entropy Carbide Based Hardmetals

“…Replacing traditional binders (Co/Ni/Fe or mixtures thereof) with high-entropy alloys (HEA) show a good wettability of WC, high toughness, prominent wear resistance, and high temperature stability. For example, by replacing Co with CoCrFeNi, CoCrFeMnNi or CoCrFeNiV binder, the plastic deformation resistance of hardmetals was enhanced, outperforming traditional WC-Co hardmetals [23,24]. In cermets too, CoCrFeNiCu can lead to less interfaces by inhibiting core-rim structure and grain growth, thus enhancing wettability, hardness, and toughness [23].…”

Combustion synthesis of TiC-based ceramic-metal composites with high entropy alloy binder

“…Using HEA binders, several cermet materials have been obtained, including WC-CoCrFeNiMn [10], Ti(C,N)-CoCrFeNiAl [11,12], TiB2-CoCrFeNiTiAl [13,14], TiB2-CoCrFeNiAl [15], and TiB2-TiC-CoCrFeNiTiAl [15]. It was suggested that such materials gave birth to a new family of cermets [17].…”