Composites

Abstract

A composite composed of two principal strengthening compounds and one principal cementing refractory metal that is prepared by combining a suitable binary to senary borides and/or carbides with a unitary to binary principal refractory metal is disclosed. As compared with the conventional sintered cemented carbides, the composite of the disclosure not only possess high hardness and high toughness but also has various ratios of principal components since it is not prepared with equal mole during the process.

Claims

1. A composite, consisting of two principal strengthening compounds and one principal cementing refractory metal, wherein one principal strengthening compound is zirconium diboride (ZrB.sub.2), the other principal strengthening compound is selected from the group consisting of TiC, VC, ZrC, HfC, WC, NbC and TaC, and the principal cementing refractory metal is tungsten (W), and the mole fraction of a total of the two principal strengthening phase compounds is 60 mol %, and the mole fraction of the principal cementing refractory metal is 40 mol %.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a flow chart of the process for preparing a composite having two principal strengthening compounds and one principal cementing refractory metal according to one embodiment of the disclosure.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(2) The following description with reference to the accompanying drawings is provided to clearly and completely explain the exemplary embodiments of the disclosure.

(3) According to the disclosure, the feature is to select appropriate binary principal strengthening compounds (borides and/or carbides) and unitary principal cementing refractory metal so as to prepare a composite having a high hardness and a high toughness.

(4) Although the product prepared by the sintering remains higher in hardness and strength under low temperatures, the process is too complicated and the toughness of the prepared product is not as desired. Thus, although it is feasible to prepare the principal strengthening compounds and the principal refractory metals by sintering, it is simpler and more rapid than sintering if they are prepared by the smelting process. In addition, the metallurgical microstructure of the product prepared by the smelting process is a typical dendritic structure, which has 100% relative density and is good in toughness. Therefore, the disclosure is explained by the embodiments employing the smelting process. However, a composite with a high hardness and a high toughness can still be prepared by the sintering if necessary according to the disclosure.

(5) As shown in FIG. 1, when using the smelting process, the method may include the following:

(6) (1) Vacuum arc smelting process furnace is used for preparing composite, the principal strengthening compound powders and bulk metal are weighted and placed evenly in a water-cooled copper mold (101);

(7) (2) The furnace cover is covered and the pressure is reduced to 2.410.sup.2 torr, pure argon is incorporated until the pressure is about 8.0 torr, and the pressure is reduced again, the purging process is repeated for three times, and then the smelting process process is performed (102); and

(8) (3) The smelting process current is 550 ampere, after the smelting process and the composite is cooled completely, the composite block is turned upside down and is smelted again; such flipping and smelting process may be repeated for 4 times for ensuring all the elements in the specimen are uniformly mixed; when the composite is cooled completely again, the vacuum may be exhausted and the ingot is obtained as a molded specimen (103).

(9) According to the embodiment of the disclosure, the composite is with two principal strengthening compounds and a principal cementing refractory metal, and one principal strengthening compound is zirconium diboride (ZrB.sub.2), the other principal strengthening compounds is selected from carbides. The mole fraction of the principal strengthening compounds and the mole fraction of the principal cementing refractory metal are different, the principal cementing refractory metal is W, and the carbide is selected from TiC, VC, ZrC, HfC, WC, NbC and TaC (Table 4).

(10) According to the first comparative embodiment, Table 1, the used boride is TiB.sub.2 (B1) and ZrB.sub.2 (B2) and the used principal cementing refractory metal is Nb, Ta, Mo and W. According to the table, it is the composite combined by a unitary boride as the principal strengthening compound and a unitary principal cementing refractory metal. Further, Table 1 shows the hardness (HV) and the toughness (K.sub.IC) of the composite composed of the unitary boride and the unitary principal cementing refractory metal.

(11) TABLE-US-00001 TABLE 1 Serial Hardness Toughness Number Component (HV) (K.sub.IC, MPa m.sup.1/2) B1Nb (TiB.sub.2).sub.0.6Nb.sub.0.4 1826 62 6.5 0.2 B1Ta (TiB.sub.2).sub.0.6Ta.sub.0.4 1832 21 X B1Mo (TiB.sub.2).sub.0.6Mo.sub.0.4 1807 22 9.1 0.3 B1W (TiB.sub.2).sub.0.6W.sub.0.4 1900 64 7.7 0.8 B2Nb (ZrB.sub.2).sub.0.6Nb.sub.0.4 1683 33 8.7 0.3 B2Ta (ZrB.sub.2).sub.0.6Ta.sub.0.4 1608 26 8.4 0.5 B2Mo (ZrB.sub.2).sub.0.6Mo.sub.0.4 1578 26 8.1 0.3 B2W (ZrB.sub.2).sub.0.6W.sub.0.4 1267 64 11.2 0.7

(12) According to the second comparative embodiment, Table 2, the used boride is TiB.sub.2 (B1) and ZrB.sub.2 (B2) and the used carbide is TiC (C1), VC (C2), ZrC (C3), HfC (C4), WC (C5), NbC (C6) and TaC (C7). The difference between W and W is the mole fraction. According to the table, it is the composite combined by unitary boride as the principal strengthening compound and unitary or binary carbide as the principal strengthening compound. Further, Table 2 shows the hardness (HV) and the toughness (K.sub.IC) of the composite having the unitary boride or the unitary or binary carbide as the principal strengthening compound and the unitary principal cementing refractory metal as the principal cementing refractory metal.

(13) TABLE-US-00002 TABLE 2 Serial Hardness Toughness Number Component (HV) (K.sub.IC, MPa m.sup.1/2) C2B1C3 (TiB.sub.2).sub.0.25(VC).sub.0.25(ZrC).sub.0.1W.sub.0.4 2199 32 7.5 0.2 C2B1C4 (TiB.sub.2).sub.0.25(VC).sub.0.25(HfC).sub.0.1W.sub.0.4 2213 80 8.1 0.4 C1B2C3 (ZrB.sub.2).sub.0.25(TiC).sub.0.25(ZrC).sub.0.1W.sub.0.4 2055 60 6.5 0.4 C1B2C3 (ZrB.sub.2).sub.0.25(TiC).sub.0.25(HfC).sub.0.1W.sub.0.4 2130 43 8.0 0.4 C1B1W (TiB.sub.2).sub.0.2(TiC).sub.0.2W.sub.0.6 1517 22 11.3 0.4 C2B1W (TiB.sub.2).sub.0.2(VC).sub.0.2W.sub.0.6 1769 33 10.5 0.2 C6B1W (TiB.sub.2).sub.0.2(ZrC).sub.0.2W.sub.0.6 1653 34 8.6 0.3 C7B1W (TiB.sub.2).sub.0.2(TaC).sub.0.2W.sub.0.6 1698 26 9.9 0.1 C1B2W (ZrB.sub.2).sub.0.2(TiC).sub.0.2W.sub.0.6 1744 16 9.7 0.1

(14) According to the third comparative embodiment, Table 3, the boride is TiB.sub.2 (B1) and the carbide is TiC (C1), VC (C2), ZrC (C3), HfC (C4), WC (C5), NbC (C6) and TaC (C7). According to the table, it is the composite combined by a unitary boride (the principal strengthening compound), a unitary carbide (the principal strengthening compound) and a unitary principal cementing refractory metal (the principal cementing refractory metal). Further, Table 3 shows the hardness (HV) and the toughness (K.sub.IC) of the composite having the unitary boride (the principal strengthening compound), the unitary carbide (the principal strengthening compound) and the unitary principal cementing refractory metal (the principal cementing refractory metal).

(15) TABLE-US-00003 TABLE 3 Serial Hardness Toughness Number Component (HV) (K.sub.IC, MPa m.sup.1/2) C1B1 [(TiC)(TiB.sub.2)].sub.0.6W.sub.0.4 1699 64 7.7 0.5 C2B1 [(VC)(TiB.sub.2)].sub.0.6W.sub.0.4 2323 34 9.8 0.3 C3B1 [(ZrC)(TiB.sub.2)].sub.0.6W.sub.0.4 1733 71 8.6 0.5 C4B1 [(HfC)(TiB.sub.2)].sub.0.6W.sub.0.4 1394 58 10.5 0.6 C5B1 [(WC)(TiB.sub.2)].sub.0.6W.sub.0.4 1463 32 6.1 0.6 C6B1 [(NbC)(TiB.sub.2)].sub.0.6W.sub.0.4 1897 31 7.6 0.4 C7B1 [(TaC)(TiB.sub.2)].sub.0.6W.sub.0.4 1935 19 9.1 0.4

(16) According to the embodiment of the present invention, Table 4, the used boride is ZrB.sub.2 (B2) and the used carbide is TiC (C1), VC (C2), ZrC (C3), HfC (C4), WC (C5), NbC (C6) and TaC (C7). According to the table, it is the composite combined by a unitary boride (the principal strengthening compound), a unitary carbide (the principal strengthening compound) and a unitary principal cementing refractory metal (the principal cementing refractory metal). Further, Table 4 shows the corresponding hardness (HV) and the toughness (K.sub.IC) of the composite having the unitary boride (the principal strengthening compound), the unitary carbide (the principal strengthening compound) and the unitary principal cementing refractory metal (the principal cementing refractory metal).

(17) TABLE-US-00004 TABLE 4 Serial Hardness Toughness Number Component (HV) (K.sub.IC, MPa m.sup.1/2) C1B2 [(TiC)(ZrB.sub.2)].sub.0.6W.sub.0.4 2195 88 8.8 0.6 C2B2 [(VC)(ZrB.sub.2)].sub.0.6W.sub.0.4 2265 57 7.4 0.4 C3B2 [(ZrC)(ZrB.sub.2)].sub.0.6W.sub.0.4 1394 52 12.1 0.6 C4B2 [(HfC)(ZrB.sub.2)].sub.0.6W.sub.0.4 1245 69 12.4 0.7 C5B2 [(WC)(ZrB.sub.2)].sub.0.6W.sub.0.4 2302 92 7.3 0.3 C6B2 [(NbC)(ZrB.sub.2)].sub.0.6W.sub.0.4 2275 89 7.2 0.6 C7B2 [(TaC)(ZrB.sub.2)].sub.0.6W.sub.0.4 2374 66 6.8 0.2

(18) According to Tables 1 to 4, when diborides (TiB.sub.2 and ZrB.sub.2) are incorporated into the system, the mechanical properties of most of the specimens may improve. Moreover, in C1B2 to C7B2, all of the hardness of the specimens significantly improves.

(19) According to the fourth to seventh comparative embodiments of the disclosure, the composite is composed of one to six principal strengthening compounds and the principal cementing refractory metal. The principal strengthening compounds may be selected from carbides, the principal cementing refractory metal may be selected from W. The mole fraction of the total principal strengthening compounds is 60 mol %, and the mole fraction of the principal cementing refractory metal is 40 mol %. In addition, the carbide is TiC, ZrC, HfC, VC, NbC, TaC and WC.

(20) According to the fourth comparative embodiment, Table 5, the used carbide is TiC (T1T9 is defined by the mole fraction) (the chemical formula is (TiC).sub.0.xW.sub.(1-0.x), x=19) and the used principal cementing refractory metal is W. According to the table, it is the composite combined by a unitary carbide (the principal strengthening compound) and a unitary W (the principal cementing refractory metal). Further, Table 5 shows the hardness (HV) and the toughness (K.sub.IC) of the composite composed of the unitary carbide (the principal strengthening compound) and the unitary W (the principal cementing refractory metal). According to the table, W has better performance in both hardness and toughness when the mole fraction of W is 40 mol %. Therefore, the following embodiments are with 40 mole % of W for the illustration purpose.

(21) TABLE-US-00005 TABLE 5 Serial Hardness Toughness Number Component (HV) (K.sub.IC, MPa m.sup.1/2) WT1 (TiC).sub.0.1W.sub.0.9 691 24 WT2 (TiC).sub.0.2W.sub.0.8 956 32 WT3 (TiC).sub.0.3W.sub.0.7 1159 27 16.2 1.1 WT4 (TiC).sub.0.4W.sub.0.6 1252 33 11.8 0.7 WT5 (TiC).sub.0.5W.sub.0.5 1461 66 8.6 0.4 WT6 (TiC).sub.0.6W.sub.0.4 1820 57 7.2 0.4 WT7 (TiC).sub.0.7W.sub.0.3 2367 110 3.8 0.8 WT8 (TiC).sub.0.8W.sub.0.2 2557 96 WT9 (TiC).sub.0.9W.sub.0.1 2770 22

(22) According to the fifth comparative embodiment, Table 6, the carbide is TiC (C1), VC (C2), ZrC (C3), HfC (C4), WC (C5), NbC (C6) and TaC (C7), and S indicates W with 40 mole %. According to the table, it is the composite combined by a unitary carbide (the principal strengthening compound) and a unitary W (the principal cementing refractory metal). Further, Table 6shows the hardness (HV) and the toughness (K.sub.IC) of the composite composed of the unitary carbide (the principal strengthening compound) and the unitary W (the principal cementing refractory metal).

(23) TABLE-US-00006 TABLE 6 Serial Hardness Toughness Number Component (HV) (K.sub.IC, MPa m.sup.1/2) SC1 (TiC).sub.0.6W.sub.0.4 1820 57 7.24 0.41 SC2 (ZrC).sub.0.6W.sub.0.4 1156 7 12.40 0.54 SC3 (HfC).sub.0.6W.sub.0.4 1279 21 11.22 0.63 SC4 (VC).sub.0.6W.sub.0.4 1675 61 4.13 0.26 SC5 (NbC).sub.0.6W.sub.0.4 1837 33 7.07 0.20 SC6 (TaC).sub.0.6W.sub.0.4 1980 33 6.82 0.12 SC7 (WC).sub.0.6W.sub.0.4 2057 60 6.16 0.18

(24) According to the sixth comparative embodiments, Table 7, NT1 indicates that the used carbide is NbC and TaC, NT2 indicates that the used carbide is NbC, TaC and TiC. NT2a, NT2b, NT2c and NT2d may have different mole ratios of the used carbide compared to NT2. In the meantime, NT2e indicates that the used carbide is TiC, ZrC, HfC, NbC and TaC, NT3 indicates that the used carbide is NbC, TaC, TiC and WC. Similarly, NT3a and NT3b may have different mole ratios of the used carbide compared with NT3. Also, NT4 indicates that the used carbide is NbC, TaC, TiC, WC and VC, and NT5 indicates that the used carbide is NbC, TaC and WC. According to the table, it is the composite combined by a binary or more of carbide (the principal strengthening compound) and a unitary W (the principal cementing refractory metal). Further, Table 7 shows the hardness (HV) and the toughness (K.sub.IC) of the composite composed of the binary or more of carbide (the principal strengthening compound) and the unitary W (the principal cementing refractory metal).

(25) TABLE-US-00007 TABLE 7 Hardness Toughness Serial Number Component (HV) (K.sub.IC, MPa m.sup.1/2) NT1 [(NbC)(TaC)].sub.0.6W.sub.0.4 2105 48 6.7 0.4 NT2 [(TiC)(NbC)(TaC)].sub.0.6W.sub.0.4 2045 81 7.7 0.6 NT2a (TiC).sub.0.24(NbC).sub.0.18(TaC).sub.0.18W.sub.0.4 1981 38 7.6 0.5 NT2b (TiC).sub.0.16(NbC).sub.0.22(TaC).sub.0.22W.sub.0.4 2096 29 7.0 0.4 NT2c {(TiC).sub.2(NbC)(TaC)}.sub.0.6W.sub.0.4 1911 70 7.3 0.4 NT2d [(ZrC)(NbC)(TaC)].sub.0.6W.sub.0.4 1459 74 7.6 0.4 NT2e (TiC).sub.0.12(ZrC).sub.0.04(HfC).sub.0.04(NbC).sub.0.2(TaC).sub.0.2W.sub.0.4 1544 44 8.1 0.2 NT3 [(TiC)(NbC)(TaC)(WC)].sub.0.6W.sub.0.4 2073 66 7.9 0.6 NT3a {(TiC).sub.2(NbC)TaC)}.sub.0.6W.sub.0.4 2165 67 8.4 0.3 NT3b {(TiC)(NbC)(TaC)(WC).sub.0.5}.sub.0.6W.sub.0.4 2120 89 7.9 0.2 NT4 [(TiC)(NbC)(TaC)(WC)(VC)].sub.0.6W.sub.0.4 2150 39 6.0 0.3 NT5 [(NbC)(TaC)(WC)].sub.0.6W.sub.0.4 2118 108 6.3 0.4

(26) According to the seventh comparative embodiments, Table 8, WC 1 indicates that the used carbide is TiC and WC, WC2 indicates that the used carbide is TiC, ZrC, HfC and WC, HE1 indicates that the used carbide is TiC, ZrC, HfC, NbC, TaC and WC, HE2 indicates that the used carbide is TiC, ZrC, HfC, VC, NbC, TaC and WC, HE3 has different mole ratio of the used carbide, as compared with HE2, MW1 indicates that the used carbide is TiC, NbC and TaC, MW2 indicates that the used carbide is TiC, NbC, TaC, WC, MW3 and MW4 have different mole ratio of the used carbide, as compared with MW2, MW5 indicates that the used carbide is NbC, and MW 6 indicates that the used carbide is TaC. According to the table, it is the composite combined by a unitary or more of carbide (the principal strengthening compound) and a unitary W (the principal cementing refractory metal). Further, Table 8 shows the hardness (HV) and the toughness (K.sub.IC) of the composite composed of the unitary or more of carbide (the principal strengthening compound) and the unitary W (the principal cementing refractory metal).

(27) TABLE-US-00008 TABLE 8 Toughness Serial Number Component Hardness (HV) (K.sub.IC, MPa m.sup.1/2) WC1 (TiC).sub.0.5(WC).sub.0.1W.sub.0.4 1873 24 7.7 0.3 WC2 [(TiC)(ZrC)(HfC)].sub.0.5(WC).sub.0.1W.sub.0.4 1260 23 10.9 0.7 HE1 [(TiC)(ZrC)(HfC)(NbC).sub.2(TaC).sub.2(WC)].sub.0.6W.sub.0.4 1601 92 7.1 0.4 HE2 [(TiC)(ZrC)(HfC)(VC)(NbC).sub.2)(TaC).sub.2(WC)].sub.0.6W.sub.0.4 1742 47 8.4 0.5 HE3 [(TiC)(ZrC)(VC(NbC).sub.2(TaC).sub.2(WC)].sub.0.6W.sub.0.4 1960 29 6.9 0.2 MW1 [(TiC)(NbC)(TaC)].sub.0.4W.sub.0.6 1423 68 10.3 0.8 MW2 [(TiC)(NbC)(TaC)(WC)].sub.0.4W.sub.0.6 1587 29 9.3 0.9 MW3 {(TiC).sub.2(NbC)(TaC)(WC)}.sub.0.4W.sub.0.6 1468 36 11.1 0.8 MW4 {(TiC)(NbC)(TaC)(WC).sub.0.5}.sub.0.4W.sub.0.6 1490 82 11.3 0.7 MW5 (NbC).sub.0.4W.sub.0.6 1585 33 7.8 0.8 MW6 (TaC).sub.0.4W.sub.0.6 1602 30 8.0 0.7

(28) According to Tables 5 to 8, NT3a and NT3b have the best performance in both hardness and toughness. The two specimens have great performance in rear and cutting resistance. In addition, most of the composite in the disclosure may be with hardness greater than 1000 HV. Thus, the disclosure is significantly better than most of the commercial ultra hard alloy.

(29) According to the disclosure, as compared to traditional technologies, the composite composed of two principal strengthening compounds and one principal cementing refractory metal of the disclosure has the following advantages:

(30) 1. The disclosure can select appropriate binary principal strengthening compounds and unitary principal cementing refractory metal so as to prepare a composite having a high hardness and a high toughness.

(31) 2. As compared to traditional cermet composites, the composite of the disclosure has a high hardness and a high toughness, and it is not prepared with equal mole during the process

(32) Note that the specifications relating to the above embodiments should be construed as exemplary rather than as limitative of the present disclosure. The equivalent variations and modifications on the structures or the process by reference to the specification and the drawings of the disclosure, or application to the other relevant technology fields directly or indirectly should be construed similarly as falling within the protection scope of the disclosure.