Complex composition alloy

Abstract

1. An alloy comprising scandium (Sc), titanium (Ti), zirconium (Zr) and / or vanadium (V), and / or their oxides, hydrides, borides and / or nitrides, in a proportion of 30 atomic % or more, wherein at least two of the elements selected from titanium, zirconium, vanadium and / or their oxides, hydrides, borides and / or carbides have a proportion of 15 atomic % or more.

Description

[Technical field]

[0001] The present invention relates to an alloy for example for a small watch part and to said small watch part comprising said alloy, in particular a small watch part intended for the casing of a small watch, such as a small watch case. The invention also relates to any other part of a means of transport or of any equipment comprising said alloy. The invention also relates to a timepiece, such as a small watch, or to a piece of jewellery, comprising said alloy. Finally, the invention relates to a method for producing said alloy. [Background technology]

[0002] Small watch cases must be very hard to provide good impact resistance and resistance to scratches that would damage the aesthetic appearance. In the state of the art, small watch cases are generally made of metal materials or metal alloys. However, it is very advantageous for small watch cases to be light in weight for comfortable wearing. The two properties of hardness and light weight are generally incompatible, since hard metals are necessarily heavy and light metals are necessarily soft. In addition to small watch cases, hard and light materials are also advantageous for many other small watch parts. For this reason, existing solutions are inadequate in that they do not allow to reach a good hardness / density compromise. Summary of the Invention [Problem to be solved by the invention]

[0003] The object of the present invention is therefore to find a solution for making small watch parts which are both stiff and light.

[0004] Of course, such a solution can advantageously achieve other advantageous or essential properties desired for small timepiece components, such as an attractive aesthetic appearance, high resistance to wear, especially resistance to oxidation and corrosion, non-magnetic properties, etc. [Means for solving the problem]

[0005] The invention therefore relates to an alloy comprising scandium (Sc) in a proportion equal to or greater than 30 atomic % and titanium (Ti), zirconium (Zr) and / or vanadium (V) and / or their oxides, hydrides, borides, carbides and / or nitrides, at least two of said elements chosen from titanium, zirconium, vanadium and / or their oxides, hydrides, borides, carbides and / or nitrides exhibiting a proportion equal to or greater than 15 atomic %.

[0006] Advantageously, the alloy is aluminium (Al) free and / or lithium (Li) free.

[0007] The alloy is Sc 30 Ti 25 V 20 Zr 25 , Sc 60 Ti 20 V 20 , Sc 33 Ti 33 V 33 , Sc 40 Ti 20 V 20 Zr 20 , Sc 33 Ti 33 Zr 33 , Sc 60 Zr 20 Ti 20 , may be selected from:

[0008] In addition, the alloy may contain magnesium (Mg) and / or manganese (Mn) and / or yttrium (Y) and / or rare earth metals.

[0009] According to an embodiment of the alloy, any element of said alloy other than scandium (Sc), titanium (Ti), zirconium (Zr) and vanadium (V) represents an atomic ratio of less than or equal to 5 atomic %, or less than or equal to 3.5 atomic %, or less than or equal to 2 atomic %, and / or the total proportion of the elements scandium (Sc), titanium (Ti), zirconium (Zr) and vanadium (V) is 70 atomic % or more, or 80 atomic % or more, or 90 atomic % or more; and / or The total proportion of the elements scandium (Sc), titanium (Ti), zirconium (Zr), vanadium (V), magnesium (Mg), manganese (Mn), yttrium (Y) and / or rare earth metals is greater than or equal to 90 atomic %, or greater than or equal to 95 atomic %.

[0010] The alloy may be made of an alloy of 4 to 13 elements.

[0011] The alloy is Scandium, at 30 atomic % or more and 70 atomic % or less, or at 40 atomic % or more and 70 atomic % or less, or at 50 atomic % or more and 65 atomic % or less, or at 30 atomic % or more and 60 atomic % or less, or at 30 atomic % or more and 47 atomic % or less, or at 30 atomic % or more and 45 atomic % or less; Titanium, at 5 atomic % or more and 35 atomic % or less, or at 5 atomic % or more and 30 atomic % or less, or at 15 atomic % or more and 25 atomic % or less, or at 15 atomic % or more and 20 atomic % or less; zirconium, from 0 atomic % to 30 atomic %, or from 5 atomic % to 30 atomic %, or from 5 atomic % to 25 atomic %, or from 15 atomic % to 25 atomic %, or from 15 atomic % to 20 atomic %, or from 10 atomic % to 20 atomic %, Vanadium, from 0 atomic % to 30 atomic %, or from 5 atomic % to 30 atomic %, or from 5 atomic % to 25 atomic %, or from 15 atomic % to 25 atomic %, or from 15 atomic % to 20 atomic %, or from 10 atomic % to 20 atomic %, may include:

[0012] Scandium may be the element of the alloy exhibiting the maximum atomic percentage.

[0013] The alloy has a strength of 4.5 g.cm, measured after forming and before any other processing. -3or less than 4.2g.cm -3 Below, or 4g.cm -3 The following densities may be indicated:

[0014] The alloy may exhibit a hardness of 400 Hv or greater, or 500 Hv or greater, or 600 Hv or greater, measured after forming and before any other processing.

[0015] The alloy may consist of scandium (Sc), titanium (Ti), zirconium (Zr) and / or vanadium (V), and / or their oxides, hydrides, borides, carbides and / or nitrides, and optionally magnesium (Mg), manganese (Mn), yttrium (Y) and / or rare earth metals.

[0016] The invention also relates to a small watch component comprising or made entirely of the above-mentioned alloy.

[0017] The miniature watch part may be a miniature watch case, a bezel, a dial, a strap link, a strap, or a clasp for a strap.

[0018] The invention also relates to a watch, in particular a miniature watch, or an article of jewellery, comprising a miniature watch part as described above or comprising an alloy as described above.

[0019] The invention also relates to specialized parts for the aeronautical sector, the automotive sector, means of transport, measuring instruments, exploration robots, weapons, or energy production or storage devices, comprising the above-mentioned alloy.

[0020] The component may be formed entirely of the alloy described above, or may be a bulk part that includes the alloy described above extending substantially through its entire thickness.

[0021] The present invention also provides crushing powders of pure elements to form alloy powders; cold compacting the alloy powder; The present invention relates to a method for producing the above-mentioned alloy or the above-mentioned part, comprising the steps of:

[0022] The forming step may include a spark plasma sintering step.

[0023] The objects, features, and advantages of the present invention are explained in detail in the following description of specific embodiments given without implied limitation. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] The present invention is based on the production and use of metal alloys that have both low density and high hardness.

[0025] For this purpose, the invention is based on the definition of a multiphase alloy with a complex composition. The concept of a complex high-concentration alloy comes in particular from high entropy alloys (HEA). High entropy alloys may consist of at least five elements that form a single solid solution in close to equimolar proportions.

[0026] More generally, mixtures of at least four elements, or at least five elements, form assemblies capable of achieving remarkable properties far removed from the usual natural properties of simple metal alloys. The definition of complex high-concentration alloys extends the definition of high-entropy alloys by including alloys composed of three or four elements, multiphase alloys, where the concentration of one of the elements advantageously exceeds 35 atomic %.

[0027] The alloy according to the invention comprises four major elements: scandium (Sc), titanium (Ti), zirconium (Zn) and vanadium (V) and / or their oxides, hydrides, borides and / or carbides. The term "major elements" is understood to refer to the fact that these elements are the four elements present in the alloy in the greatest proportion. Preferably, these four major elements represent at least 70 atomic % or more, or 80 atomic % or more, or 90 atomic % or more (the percentages are therefore atomic percentages) of the alloy.

[0028] The alloy according to the invention contains scandium in a proportion of at least 30 atomic % and, in addition, at least two of the elements titanium, zirconium and vanadium are present in a proportion of at least 15 atomic %.

[0029] Each major element participates in contributing to the alloy's advantageous properties. For example, scandium contributes light weight, color, and mechanical properties; titanium contributes hardness; zirconium contributes resistance to oxidation; and vanadium contributes hardness.

[0030] Moreover, the combination of these four main elements makes it possible to form multiphase alloys with complex compositions. The combination makes it possible to form alloys with remarkable properties that go far beyond the simple addition of the properties of each element, as will be explained below. To obtain said alloys, it was necessary to make a selection of elements whose chemical compatibility between them was found to be particularly good.

[0031] According to a first embodiment of the invention, the alloy consists of these four main elements, among which the following alloys can be identified (the indices indicate the atomic percentage of each element): -Sc 30 Ti 25 V 20 Zr 25 -Sc 40 Ti 20 V 20 Zr 20

[0032] In simplified alternatives, the embodiment may be free of zirconium or free of vanadium. By way of example, the following alloys may be used in the context of the present invention: -Sc 60 Ti 20 V 20 -Sc 33 Ti 33 V 33 -Sc 33 Zr 33 Ti 33 -Sc 60 Zr 20 Ti 20 .

[0033] Advantageously, the alloy does not contain aluminum (Al) or lithium (Li), in other words, the alloy does not contain detectable signs of aluminum and / or lithium. Aluminum is highly reactive with scandium, forming intermetallic compounds that can weaken the alloy. Lithium has a high volatility, which complicates processing and weakens the alloy by forming intermetallic compounds.

[0034] As mentioned above, the alloy may include one of the oxides and / or nitrides and / or hydrides and / or borides and / or carbides of the elements scandium, titanium, zirconium, and vanadium.

[0035] According to a second embodiment of the invention, the alloy comprises at least one other "secondary" element, which may be magnesium (Mg) and / or manganese (Mn) and / or yttrium (Y) and / or a rare earth metal.

[0036] Advantageously, any secondary element is present in an atomic ratio of less than or equal to 5 atomic %, or less than or equal to 3.5 atomic %, or less than or equal to 2 atomic %.

[0037] Also advantageously, the total proportion of the elements scandium (Sc), titanium (Ti), zirconium (Zr), vanadium (V), magnesium (Mg), manganese (Mn), yttrium (Y) and / or rare earth metals is greater than or equal to 90 atomic %, or greater than or equal to 95 atomic %.

[0038] Finally, the alloy according to the invention may contain 3, 4 or 5 elements. Alternatively, the alloy may contain more than 5 elements, in particular between 6 and 13 elements.

[0039] Thus, the alloy may consist of scandium (Sc), titanium (Ti), zirconium (Zr) and / or vanadium (V), and optionally magnesium (Mg), manganese (Mn), yttrium (Y) and / or rare earth metals.

[0040] Advantageously, in all embodiments, each of the four main elements is present in the following atomic ratios: - Scandium, with a content of 30 atomic % to 70 atomic %, or 40 atomic % to 70 atomic %, or 50 atomic % to 65 atomic %, or 30 atomic % to 60 atomic %, or 30 atomic % to 47 atomic %, or 30 atomic % to 45 atomic %, and - titanium, with a concentration of 5 atomic % to 35 atomic %, or with a concentration of 5 atomic % to 30 atomic %, or with a concentration of 15 atomic % to 25 atomic %, or with a concentration of 15 atomic % to 20 atomic %, - zirconium, with a concentration of 0 atomic % to 30 atomic %, or with a concentration of 5 atomic % to 30 atomic %, or with a concentration of 5 atomic % to 25 atomic %, or with a concentration of 15 atomic % to 25 atomic %, or with a concentration of 15 atomic % to 20 atomic %, or with a concentration of 10 atomic % to 20 atomic %, and - Vanadium, from 0 atomic % to 30 atomic %, or from 5 atomic % to 30 atomic %, or from 5 atomic % to 25 atomic %, or from 15 atomic % to 25 atomic %, or from 15 atomic % to 20 atomic %, or from 10 atomic % to 20 atomic %.

[0041] Advantageously, in all embodiments of the present invention, scandium is present in the greatest atomic percentage.

[0042] Such alloys according to the invention appear to be capable of achieving low density and high hardness. Advantageously, the alloy elements have a hardness of 4.5 g.cm, measured after the forming step described below and before any optional processing of the resulting alloy. -3 or 4.2g.cm -3 Below, or 4g.cm -3The alloys are selected to exhibit a density of 0.1 to 1.0 mm and a hardness of 400 Hv or more, or 500 Hv or more, or 600 Hv or more. It is also notable that the alloys of the present invention exhibit high microstructural stability, capable of withstanding temperatures of greater than 900° C., or greater than 1000° C.

[0043] Advantageously, the alloy is a fully metallic alloy. The invention appears to make it possible to obtain an alloy that is completely rust-free, non-magnetic, lighter than aluminium and harder than hardened steel.

[0044] The alloy may have a simple, single-phase or two-phase, crystalline, in particular nanocrystalline, structure, or alternatively, the alloy may exhibit an amorphous structure.

[0045] The invention also relates to a small watch part, which comprises an alloy as described above. According to one embodiment, the small watch part may be entirely made of the alloy according to the invention. In the alternative, only a part of the part may be made of the alloy.

[0046] According to one embodiment, the miniature watch part may be a miniature watch case, a bezel, a dial, a strap link, a strap (bracelet), a strap clasp, or the like.

[0047] The invention also relates to a timepiece or jewellery comprising the alloy described above or comprising a miniature timepiece part as described above.A timepiece according to an embodiment of the invention may be a miniature timepiece, such as a wristwatch.

[0048] The invention is designed for the watchmaking sector and for the jewellery sector. However, the alloy according to the invention may advantageously be used in other sectors as a result of its many outstanding properties. It may thus be used, for example, in the aerospace, aviation or automotive sector, more generally in all transport industries, and in the energy and weapons sectors. The invention therefore also relates to dedicated parts in the aerospace, aviation or automotive sector, means of transport, measuring instruments, for example measuring robots and / or space exploration robots, energy production or storage devices, etc., made entirely or in part of the alloy according to the invention. The parts containing the alloy advantageously consist entirely of the alloy, i.e. the alloy forms the bulk part. The alloy extends over the entire thickness of the part. In an alternative, such parts may be mainly made of the alloy, in particular extending to its core. The alloy may optionally be covered by a surface coating to give a particular colour or a particular appearance or a particular surface protection.

[0049] Finally, the present invention also relates to a method for producing the above-mentioned alloy. Methods for producing high entropy alloys and alloys containing multiple elements already exist.

[0050] In the alloy according to the invention, the elements are highly reactive in the liquid phase: molten scandium, for example, is very difficult to handle in the liquid phase, and liquid titanium is highly reactive with atmospheric oxygen, forming weakening oxides.

[0051] Therefore, according to an embodiment of the present invention, the manufacturing method includes a mechanical alloying step.

[0052] More specifically, in the first step of the method, the pure elements of the alloy to be produced, in powder form, are placed in a high-energy planetary mill. The energy generated by the impact between the beads of the mill and the powder of the pure elements has two effects: - A first mechanical crushing effect that allows the various elements to come into contact. The ductile particles deform to surround the solid particles. - The second effect is the heat generated by the impact, which activates the solid-state diffusion of the elements and allows the alloy to melt. After a given crushing time, the result is a new alloy powder with a uniform composition. Incidentally, crushing is carried out under vacuum or in the presence of an inert gas.

[0053] The alloy powder is then compacted in a second step.

[0054] The technique used to form the alloy is Spark Plasma Sintering. The Spark Plasma Sintering technique consists of the simultaneous application of a pulsed electric current and pressure to the powder. Spark Plasma Sintering makes it possible to use low sintering temperatures and reduced times maintained under pressure, thus making it possible to obtain rapid sintering. The technique makes it possible to obtain a fine microstructure, the dimensions of whose particles are in the nanometer size range.

[0055] Incidentally, the second stage uses a low sintering temperature to avoid any risk of evaporation and a short duration to avoid any risk of decomposition of the alloy.

[0056] After densification, the sintered shape obtained in the second step may be subjected to any conventional treatment in a third step, for example the sintered shape may be conventionally machined.

Claims

1. Scandium (Sc) at a ratio of 30 atomic % or more; Titanium (Ti), zirconium (Zr) and / or vanadium (V), and / or their oxides, hydrides, borides, carbides and / or nitrides, At least two of the elements selected from titanium, zirconium, vanadium, and / or oxides, hydrides, borides, carbides, and / or nitrides thereof are present in a proportion of 15 atomic % or more; alloy.

2. The alloy does not contain aluminum (Al), and / or The alloy does not contain lithium (Li).

10. The alloy of claim 1.

3. The alloy Sc ３０ Ti ２５ V ２０ Zr ２５ 、 Sc ６０ Today ２０ V ２０ 、 Sc ３３ Today ３３ V ３３ 、 Sc ４０ Ti ２０ V ２０ Zr ２０ 、 Sc ３３ Ti ３３ Zr ３３ 、 Sc ６０ Zr ２０ Ti ２０ 、 Selected from: The alloy of claim 2.

4. The alloy comprises magnesium (Mg) and / or manganese (Mn) and / or yttrium (Y) and / or rare earth metals.

10. The alloy of claim 1.

5. any element of said alloy other than scandium (Sc), titanium (Ti), zirconium (Zr) and vanadium (V) represents an atomic proportion of less than or equal to 5 atomic %; and / or the total proportion of the elements scandium (Sc), titanium (Ti), zirconium (Zr) and vanadium (V) is equal to or greater than 70 atomic percent; and / or the total proportion of the elements scandium (Sc), titanium (Ti), zirconium (Zr), vanadium (V), magnesium (Mg), manganese (Mn), yttrium (Y) and / or rare earth metals is 90 atomic % or more; 10. The alloy of claim 1.

6. The alloy is composed of an alloy of 4 to 13 elements. The alloy of claim 4.

7. The alloy 30 atomic % or more and 70 atomic % or less of scandium; 5 atomic % or more and 35 atomic % or less of titanium; 0 atomic % or more and 30 atomic % or less of zirconium; 0 atomic % or more and 30 atomic % or less of vanadium; Including, 10. The alloy of claim 1.

8. The element of the alloy presenting the largest atomic percentage is scandium; 10. The alloy of claim 1.

9. The alloy has a modulus of 4.5 g.cm, measured after forming the alloy and before any other processing. －３ Showing the density of:

10. The alloy of claim 1.

10. The alloy exhibits a hardness of 400 Hv or greater, measured after forming the alloy and before any other processing.

10. The alloy of claim 1.

11. The alloy consists of scandium (Sc), titanium (Ti), zirconium (Zr) and / or vanadium (V), and / or oxides, hydrides, borides, carbides and / or nitrides thereof, and optionally magnesium (Mg), manganese (Mn), yttrium (Y) and / or rare earth metals.

10. The alloy of claim 1.

12. A small watch component comprising the alloy of claim 1.

13. Small watch cases, bezels, dials, strap links, straps, or strap clasps, 13. A small watch part according to claim 12.

14. A timepiece comprising a miniature timepiece component according to claim 12.

15. 10. A specialized part for the aeronautical sector, the automotive sector, a means of transport, a measuring instrument, a robotic probe, a weapon, or an energy production or storage device, comprising the alloy of claim 1.

16. A bulk part comprising said alloy extending substantially through the entire thickness of the bulk part.

13. The component of claim 12.

17. crushing powders of pure elements to form alloy powders; cold compacting the alloy powder; Including stages, A method for manufacturing the component of claim 12.

18. 18. A method for producing an alloy or component according to claim 17, wherein the shaping step comprises a spark plasma sintering step.

19. Any element of the alloy other than scandium (Sc), titanium (Ti), zirconium (Zr) and vanadium (V) represents an atomic ratio of less than or equal to 2 atomic %; and / or the total proportion of the elements scandium (Sc), titanium (Ti), zirconium (Zr) and vanadium (V) is equal to or greater than 90 atomic percent; and / or the total proportion of the elements scandium (Sc), titanium (Ti), zirconium (Zr), vanadium (V), magnesium (Mg), manganese (Mn), yttrium (Y) and / or rare earth metals is 95 atomic % or more; The alloy of claim 5.

20. Scandium at 30 atomic % or more and 45 atomic % or less, 15 atomic % or more and 20 atomic % or less of titanium; 10 atomic % or more and 20 atomic % or less of zirconium; 10 atomic % or more and 20 atomic % or less of vanadium; Including, 8. The alloy of claim 7.