METALLIC MULTICOMPONENT CARBIDES

Abstract

A multicomponent carbide has at least five transition metals, and a valence electron concentration (VEC) is greater 8.80 electrons. Preferred off-equiatomic multicomponent carbides have five transition metals and a VEC of more than 8.80. Preferred equiatomic multicomponent carbides have five transition metals and a VEC of 9.00 or greater. The valence electron configuration is important for its relationship to the mechanical properties of carbides. Since carbon forms four bonds, when there are more than four valence electrons available from the metals, there are excess electrons in the system. This increases metallic character of bonding and therefore allows for more ductility and higher toughness.

Claims

1. A metallic multicomponent carbide comprising at least five transition metals wherein the valence electron concentration is greater 8.80 electrons.

2. The metallic multicomponent carbide of claim 1, comprising a transition metal composition varied from equiatomic proportions to obtain the valence electron concentration of greater than 8.80 electrons.

3. The metallic multicomponent carbide of claim 2, consisting of one of the following compositions: TABLE-US-00005 Composition VEC (Hf.sub.0.18Mo.sub.0.28Nb.sub.0.18Ta.sub.0.18Ti.sub.0.18)C 8.92 (Hf.sub.0.18Mo.sub.0.28Nb.sub.0.18Ta.sub.0.18Zr.sub.0.18)C 8.92 (Hf.sub.0.18Mo.sub.0.28Nb.sub.0.18Ti.sub.0.18V.sub.0.18)C 8.92 (Mo.sub.0.28Nb.sub.0.18Ta.sub.0.18Ti.sub.0.18Zr.sub.0.18)C 8.92 (Hf.sub.0.18Mo.sub.0.28Ta.sub.0.18Ti.sub.0.18V.sub.0.18)C 8.92 (Hf.sub.0.18Nb.sub.0.18Ta.sub.0.18Ti.sub.0.18W.sub.0.28)C 8.92 (Hf.sub.0.18Nb.sub.0.18Ta.sub.0.18W.sub.0.28Zr.sub.0.18)C 8.92 (Hf.sub.0.18Nb.sub.0.18Ti.sub.0.18V.sub.0.18W.sub.0.28)C 8.92 (Mo.sub.0.28Nb.sub.0.18Ti.sub.0.18V.sub.0.18Zr.sub.0.18)C 8.92 (Mo.sub.0.28Ta.sub.0.18Ti.sub.0.18V.sub.0.18Zr.sub.0.18)C 8.92 (Nb.sub.0.18Ta.sub.0.18Ti.sub.0.18W.sub.0.28Zr.sub.0.18)C 8.92 (Hf.sub.0.18Ta.sub.0.18Ti.sub.0.18V.sub.0.18W.sub.0.28)C 8.92 (Hf.sub.0.18Mo.sub.0.28Nb.sub.0.18V.sub.0.18Zr.sub.0.18)C 8.92 (Hf.sub.0.18Mo.sub.0.28Ta.sub.0.18V.sub.0.18Zr.sub.0.18)C 8.92 (Nb.sub.0.18Ti.sub.0.18V.sub.0.18W.sub.0.28Zr.sub.0.18)C 8.92 (Ta.sub.0.18Ti.sub.0.18V.sub.0.18W.sub.0.28Zr.sub.0.18)C 8.92 (Hf.sub.0.18Nb.sub.0.18V.sub.0.18W.sub.0.28Zr.sub.0.18)C 8.92 (Hf.sub.0.18Ta.sub.0.18V.sub.0.18W.sub.0.28Zr.sub.0.18)C 8.92

4. The metallic multicomponent carbide of claim 1, comprising an equiatomic multicomponent carbide with five transition metals and a VEC of 9.00 or greater.

5. The metallic multicomponent carbide of claim 4, consisting of one of the following compositions: TABLE-US-00006 Composition VEC (Mo.sub.0.2Nb.sub.0.2Ta.sub.0.2V.sub.0.2W.sub.0.2)C 9.40 (Mo.sub.0.2Nb.sub.0.2Ta.sub.0.2Ti.sub.0.2W.sub.0.2)C 9.20 (Hf.sub.0.2Mo.sub.0.2Nb.sub.0.2Ta.sub.0.2W.sub.0.2)C 9.20 (Mo.sub.0.2Nb.sub.0.2Ti.sub.0.2V.sub.0.2W.sub.0.2)C 9.20 (Mo.sub.0.2Ta.sub.0.2Ti.sub.0.2V.sub.0.2W.sub.0.2)C 9.20 (Mo.sub.0.2Nb.sub.0.2Ta.sub.0.2W.sub.0.2Zr.sub.0.2)C 9.20 (Hf.sub.0.2Mo.sub.0.2Nb.sub.0.2V.sub.0.2W.sub.0.2)C 9.20 (Hf.sub.0.2Mo.sub.0.2Ta.sub.0.2V.sub.0.2W.sub.0.2)C 9.20 (Mo.sub.0.2Nb.sub.0.2V.sub.0.2W.sub.0.2Zr.sub.0.2)C 9.20 (Mo.sub.0.2Ta.sub.0.2V.sub.0.2W.sub.0.2Zr.sub.0.2)C 9.20 (Mo.sub.0.2Nb.sub.0.2Ta.sub.0.2Ti.sub.0.2V.sub.0.2)C 9.00 (Nb.sub.0.2Ta.sub.0.2Ti.sub.0.2V.sub.0.2W.sub.0.2)C 9.00 (Hf.sub.0.2Mo.sub.0.2Nb.sub.0.2Ta.sub.0.2V.sub.0.2)C 9.00 (Hf.sub.0.2Nb.sub.0.2Ta.sub.0.2V.sub.0.2W.sub.0.2)C 9.00 (Mo.sub.0.2Nb.sub.0.2Ta.sub.0.2V.sub.0.2Zr.sub.0.2)C 9.00 (Nb.sub.0.2Ta.sub.0.2V.sub.0.2W.sub.0.2Zr.sub.0.2)C 9.00 (Hf.sub.0.2Mo.sub.0.2Nb.sub.0.2Ti.sub.0.2W.sub.0.2)C 9.00 (Hf.sub.0.2Mo.sub.0.2Ta.sub.0.2Ti.sub.0.2W.sub.0.2)C 9.00 (Hf.sub.0.2Mo.sub.0.2Nb.sub.0.2W.sub.0.2Zr.sub.0.2)C 9.00 (Mo.sub.0.2Nb.sub.0.2Ti.sub.0.2W.sub.0.2Zr.sub.0.2)C 9.00 (Mo.sub.0.2Ta.sub.0.2Ti.sub.0.2W.sub.0.2Zr.sub.0.2)C 9.00 (Hf.sub.0.2Mo.sub.0.2Ta.sub.0.2W.sub.0.2Zr.sub.0.2)C 9.00 (Hf.sub.0.2Mo.sub.0.2Ti.sub.0.2V.sub.0.2W.sub.0.2)C 9.00 (Mo.sub.0.2Ti.sub.0.2V.sub.0.2W.sub.0.2Zr.sub.0.2)C 9.00 (Hf.sub.0.2Mo.sub.0.2V.sub.0.2W.sub.0.2Zr.sub.0.2)C 9.00

6. The metallic multicomponent carbide of claim 1, consisting of (Hf.sub.0.2Mo.sub.0.2Ti.sub.0.2W.sub.0.2Zr.sub.0.2)C.

7. The metallic multicomponent carbide of claim 1, consisting of Mo.sub.0.2Nb.sub.0.2Ta.sub.0.2V.sub.0.2W.sub.0.2)C.

8. A high entropy metal carbide ceramic according to claim 1, having the composition selected from the following: TABLE-US-00007 Composition (Hf.sub.0.2Ta.sub.0.2Ti.sub.0.2W.sub.0.2Zr.sub.0.2)C. VEC 8.6 (Mo.sub.0.2Nb.sub.0.2Ta.sub.0.2Ti.sub.0.2V.sub.0.2)C VEC 9 (Hf.sub.0.2Mo.sub.0.2Ta.sub.0.2Ti.sub.0.2Zr.sub.0.2)C VEC 8.6 (Hf.sub.0.2Mo.sub.0.2Nb.sub.0.2Ta.sub.0.2Ti.sub.0.2)C. VEC 8.8 (Mo.sub.0.2Nb.sub.0.2Ta.sub.0.2V.sub.0.2W.sub.0.2)C VEC 9.4

Description

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Preferred embodiments of the invention provide multicomponent carbides having at least five transition metals having a valence electron concentration of more than 8.80, or at least 8.80 and including two Group VI transition metals. During making a preferred multicomponent carbides, the transition metal compositions are varied from equiatomic proportions to obtain a valence electron concentration of greater than 8.80 electrons per formula unit. The multi-component carbides of the invention are metallic in bonding confirmation and provide high ductility and toughness.

[0013] Preferred multicomponent carbides of the invention include Equiatomic compositions with a VEC of 9.00 or greater. Additional multicomponent carbides of the invention include Off-Equiatomic compositions with a VEC greater than 8.80 or at least 8.80 and including two Group VI transition metals.

[0014] The valence electron concentration (VEC) is defined as the total number of valence electrons per formula unit. For example, in TiC there are two s orbital and two d orbital electrons per titanium atom (4s.sup.23d.sup.2) and two s orbital and two p orbital electrons per carbon atom (2s.sup.22p.sup.2) for a total of 8.00 electrons/formula unit or a VEC=8. For a solid solution such as (Zr.sub.0.5Nb.sub.0.5)C, there are two s orbital and two d orbital electrons per zirconium atom (5s.sup.24d.sup.2) and two s orbital and three d orbital electrons per niobium atom (5s.sup.14d.sup.4) and two s orbital and two p orbital electrons per carbon atom (2s.sup.22p.sup.2). So, there are (4*0.5)=2 from titanium, (5*0.5)=2.5 from niobium, and 4 from carbon for a total VEC of 8.50 electrons per formula unit. The inclusion of group VIB transition metals allows for high valence electron configurations to be achieved, for example (Nb.sub.0.5W.sub.0.5)C has a VEC of 9.50 electrons per formula unit.

[0015] For multicomponent carbides with five transition metals, we have identified the valence electron configuration is important for its relationship to the mechanical properties of carbides. Since carbon forms four bonds, when there are more than four valence electrons available from the metals, there are excess electrons in the system. This increases metallic character of bonding and therefore allows for more ductility and higher toughness.

[0016] Table 1 includes preferred equiatomic multicomponent carbides with five transition metals and a VEC of 9.00 or greater.

TABLE-US-00001 Composition VEC (Mo.sub.0.2Nb.sub.0.2Ta.sub.0.2V.sub.0.2W.sub.0.2)C 9.40 (Mo.sub.0.2Nb.sub.0.2Ta.sub.0.2Ti.sub.0.2W.sub.0.2)C 9.20 (Hf.sub.0.2Mo.sub.0.2Nb.sub.0.2Ta.sub.0.2W.sub.0.2)C 9.20 (Mo.sub.0.2Nb.sub.0.2Ti.sub.0.2V.sub.0.2W.sub.0.2)C 9.20 (Mo.sub.0.2Ta.sub.0.2Ti.sub.0.2V.sub.0.2W.sub.0.2)C 9.20 (Mo.sub.0.2Nb.sub.0.2Ta.sub.0.2W.sub.0.2Zr.sub.0.2)C 9.20 (Hf.sub.0.2Mo.sub.0.2Nb.sub.0.2V.sub.0.2W.sub.0.2)C 9.20 (Hf.sub.0.2Mo.sub.0.2Ta.sub.0.2V.sub.0.2W.sub.0.2)C 9.20 (Mo.sub.0.2Nb.sub.0.2V.sub.0.2W.sub.0.2Zr.sub.0.2)C 9.20 (Mo.sub.0.2Ta.sub.0.2V.sub.0.2W.sub.0.2Zr.sub.0.2)C 9.20 (Mo.sub.0.2Nb.sub.0.2Ta.sub.0.2Ti.sub.0.2V.sub.0.2)C 9.00 (Nb.sub.0.2Ta.sub.0.2Ti.sub.0.2V.sub.0.2W.sub.0.2)C 9.00 (Hf.sub.0.2Mo.sub.0.2Nb.sub.0.2Ta.sub.0.2V.sub.0.2)C 9.00 (Hf.sub.0.2Nb.sub.0.2Ta.sub.0.2V.sub.0.2W.sub.0.2)C 9.00 (Mo.sub.0.2Nb.sub.0.2Ta.sub.0.2V.sub.0.2Zr.sub.0.2)C 9.00 (Nb.sub.0.2Ta.sub.0.2V.sub.0.2W.sub.0.2Zr.sub.0.2)C 9.00 (Hf.sub.0.2Mo.sub.0.2Nb.sub.0.2Ti.sub.0.2W.sub.0.2)C 9.00 (Hf.sub.0.2Mo.sub.0.2Ta.sub.0.2Ti.sub.0.2W.sub.0.2)C 9.00 (Hf.sub.0.2Mo.sub.0.2Nb.sub.0.2W.sub.0.2Zr.sub.0.2)C 9.00 (Mo.sub.0.2Nb.sub.0.2Ti.sub.0.2W.sub.0.2Zr.sub.0.2)C 9.00 (Mo.sub.0.2Ta.sub.0.2Ti.sub.0.2W.sub.0.2Zr.sub.0.2)C 9.00 (Hf.sub.0.2Mo.sub.0.2Ta.sub.0.2W.sub.0.2Zr.sub.0.2)C 9.00 (Hf.sub.0.2Mo.sub.0.2Ti.sub.0.2V.sub.0.2W.sub.0.2)C 9.00 (Mo.sub.0.2Ti.sub.0.2V.sub.0.2W.sub.0.2Zr.sub.0.2)C 9.00 (Hf.sub.0.2Mo.sub.0.2V.sub.0.2W.sub.0.2Zr.sub.0.2)C 9.00

[0017] Table 2 includes preferred off-equiatomic multicomponent carbides with five transition metals and a VEC of more than 8.80.

TABLE-US-00002 Composition VEC (Hf.sub.0.18Mo.sub.0.28Nb.sub.0.18Ta.sub.0.18Ti.sub.0.18)C 8.92 (Hf.sub.0.18Mo.sub.0.28Nb.sub.0.18Ta.sub.0.18Zr.sub.0.18)C 8.92 (Hf.sub.0.18Mo.sub.0.28Nb.sub.0.18Ti.sub.0.18V.sub.0.18)C 8.92 (Mo.sub.0.28Nb.sub.0.18Ta.sub.0.18Ti.sub.0.18Zr.sub.0.18)C 8.92 (Hf.sub.0.18Mo.sub.0.28Ta.sub.0.18Ti.sub.0.18V.sub.0.18)C 8.92 (Hf.sub.0.18Nb.sub.0.18Ta.sub.0.18Ti.sub.0.18W.sub.0.28)C 8.92 (Hf.sub.0.18Nb.sub.0.18Ta.sub.0.18W.sub.0.28Zr.sub.0.18)C 8.92 (Hf.sub.0.18Nb.sub.0.18Ti.sub.0.18V.sub.0.18W.sub.0.28)C 8.92 (Mo.sub.0.28Nb.sub.0.18Ti.sub.0.18V.sub.0.18Zr.sub.0.18)C 8.92 (Mo.sub.0.28Ta.sub.0.18Ti.sub.0.18V.sub.0.18Zr.sub.0.18)C 8.92 (Nb.sub.0.18Ta.sub.0.18Ti.sub.0.18W.sub.0.28Zr.sub.0.18)C 8.92 (Hf.sub.0.18Ta.sub.0.18Ti.sub.0.18V.sub.0.18W.sub.0.28)C 8.92 (Hf.sub.0.18Mo.sub.0.28Nb.sub.0.18V.sub.0.18Zr.sub.0.18)C 8.92 (Hf.sub.0.18Mo.sub.0.28Ta.sub.0.18V.sub.0.18Zr.sub.0.18)C 8.92 (Nb.sub.0.18Ti.sub.0.18V.sub.0.18W.sub.0.28Zr.sub.0.18)C 8.92 (Ta.sub.0.18Ti.sub.0.18V.sub.0.18W.sub.0.28Zr.sub.0.18)C 8.92 (Hf.sub.0.18Nb.sub.0.18V.sub.0.18W.sub.0.28Zr.sub.0.18)C 8.92 (Hf.sub.0.18Ta.sub.0.18V.sub.0.18W.sub.0.28Zr.sub.0.18)C 8.92

[0018] Table 3 consists of the preferred off-equiatomic multicomponent carbide with five transition metals, of which two are Group VI elements.

TABLE-US-00003 Composition VEC (Hf.sub.0.2Mo.sub.0.2Ti.sub.0.2W.sub.0.2Zr.sub.0.2)C 8.80

[0019] The preferred compositions are preferably made by mixing the proper ratios of the corresponding 5 binary carbides, ball milling them together and then sintering at suitable temperature and pressure to achieve a high density product. Alternatively, the materials can be fabricated by mixing the proper ratios of the metal powders with the appropriate amounts of carbon to achieve the monocarbide composition, followed by ball milling and sintering. In a further embodiment of the synthesis route, the metal oxides of the 5 metal species can be combined with appropriate amounts of carbon to achieve a reduction of the oxides to metallic species and subsequent carbide formation using similar sintering techniques.

[0020] Table 4 consists of additional preferred multicomponent carbide with five transition metals with at least on Group VI element, and the most preferred having two Group VI elements and a VEC of 9.4:

TABLE-US-00004 Composition (Hf.sub.0.2Ta.sub.0.2Ti.sub.0.2W.sub.0.2Zr.sub.0.2)C.  3 IV, 1 V, 1 VI = VEC 8.6 (Mo.sub.0.2Nb.sub.0.2Ta.sub.0.2Ti.sub.0.2V.sub.0.2)C 1 IV, 3 V, 1 VI = VEC 9  (Hf.sub.0.2Mo.sub.0.2Ta.sub.0.2Ti.sub.0.2Zr.sub.0.2)C  3 IV, 1 V, 1 VI = VEC 8.6  (Hf.sub.0.2Mo.sub.0.2Nb.sub.0.2Ta.sub.0.2Ti.sub.0.2)C.  2 IV, 2 V, 1 VI = VEC 8.8 (Mo.sub.0.2Nb.sub.0.2Ta.sub.0.2V.sub.0.2W.sub.0.2)C  0 IV, 3 V, 2 VI = VEC 9.4

[0021] Some of the compositions have been made and tested. Selected properties demonstrate the surprising and superior hardness of many of the compositions over the hardness predicted by a rule-of-mixtures approach of the corresponding binary carbide compositions.

[0022] The present approach provides a new method for designing super-hard materials. The present methods provide a foundation for a long-sought enabler of accelerated design for high-entropy ceramics with enhanced properties for a wide range of different technological applications.

[0023] While specific embodiments of the present invention have been shown and described, it should be understood that other modifications, substitutions and alternatives are apparent to one of ordinary skill in the art. Such modifications, substitutions and alternatives can be made without departing from the spirit and scope of the invention, which should be determined from the appended claims.

[0024] Various features of the invention are set forth in the appended claims.