EP4026923A1

EP4026923A1 - Gold and titanium based alloy

Info

Publication number: EP4026923A1
Application number: EP21150617.5A
Authority: EP
Inventors: Céline GUIDOUX; Damien Colas
Original assignee: Officine Panerai AG
Current assignee: Officine Panerai AG
Priority date: 2021-01-07
Filing date: 2021-01-07
Publication date: 2022-07-13
Also published as: WO2022148817A1; EP4274916A1

Abstract

The invention relates to an alloy comprising 375 to 917 parts of gold, 83 to 625 parts of titanium, and 30 to 200 ppm of a grain refiner selected from iridium, bore, vanadium, iron, cobalt, barium, yttrium, zirconium, and mixtures thereof. The invention also relates to a process for preparing this alloy and to an item (watch or jewel) comprising or consisting of this alloy.

Description

FIELD OF THE INVENTION

The invention relates to an alloy based on gold and titanium. This alloy, which also comprises a specific amount of grain refiner, can be used in horology or jewelry.

BACKGROUND OF THE INVENTION

Due to their properties, such as hardness or tensile strength, gold-titanium based alloys are commonly used in fields such as dentistry, ceramics, horology or jewelry.
For instance, WO 2008/018109 discloses an alloy comprising 25-75 wt% of gold and titanium, as well as 0-40 wt% of nickel.
Ti₃Au (in mole fraction) exhibits hardness values above most steels and approximately four times those of titanium.
WO 2018/162745 discloses a material having a thin layer of Ti_1-xAu_x, in which the atomic fraction x is from 0.22 to 0.28, for instance 0.25 as in Ti₃Au.
However, specific applications, for instance in horology or jewelry, require alloys having a greater gold fraction than in Ti₃Au.
For instance, WO 2016/107755 discloses an alloy comprising at least 750 wt% (18 carats) of gold. This alloy is made of:

41 to 49.5 at% Au
45 to 55 at% Ti
2.5 to 13 at% Nb, V, Pd, Pt, Fe
0.1 to 2.5 at% at least one of Nb, V, Pd, Pt, Fe, Mo, Ta, W, Co, Ni, Ru, Rh, Ir, Cr, Mn, Cu, Zn, Ag, Al, B, Si, Ge, Sn, Sb, In.

In addition to gold and titanium, this alloy comprises at least two alloying elements, as in Au_0.427Ti_0.50Fe_0.072B₀.₀₀₁ (in mole fraction) i.e., by weight, Au₇₅₀Ti₂₁₃Fe₃₆B₁, in which the total amount of iron and boron represents 37 000 ppm by weight vs gold and titanium.
Even though most of the above alloys can be used in jewelry or horology, there is still an interest in improving the properties of light colored gold alloys. Applicant has discovered that a small amount of grain refiner in gold-titanium alloys allows the formation of small grains, improves the hardness, and prevents the formation of cracks.

SUMMARY OF THE INVENTION

The invention relates to a binary alloy (two main elements) having improved properties due to the presence of a small amount of a specific grain refiner. This alloy is easy to shape by mechanical deformation since it exhibits a small shape memory effect, smaller than that of conventional gold-titanium alloys.
More specifically, the invention relates to an alloy of formula Au_xTi_yR_z, wherein:

x = 375 to 917 parts by weight,
y = 83 to 625 parts by weight,
x + y = 1000 parts by weight,
z = 30 to 200 ppm by weight of x + y,
and wherein R is a grain refiner selected from the group consisting of iridium, bore, vanadium, iron, cobalt, barium, yttrium, zirconium, and mixtures thereof.

This alloys consists in gold, titanium and one or more grain refiner selected from a specific list of elements.
The amount of grain refiner is 30 to 200 ppm by weight with respect to the total amount of gold and titanium.
All ranges include the end-points. For instance the "375 to 917" and "between 375 and 917" ranges include the 375 and 917 values.
According to a preferred embodiment, the alloy comprises a single grain refiner, preferably iridium (R = iridium). The alloy can therefore consists of three elements: gold, titanium and one grain refiner, for instance gold, titanium and iridium.
In the alloy of formula Au_xTi_yR_z, the amount z of grain refiner ranges from 30 to 200 ppm by weight when x + y is equal to 1000 parts by weight. According to a preferred embodiment, z ranges from 40 to 100 ppm, more preferably from 40 to 60 ppm, even more preferably z is equal to 50 ppm.
In the alloy of formula Au_xTi_yR_z, the amount x of gold ranges from 375 to 917 parts by weight. It preferably ranges from 580 to 760 parts by weight.
In the alloy of formula Au_xTi_yR_z, the amount y of titanium ranges from 83 to 625 parts by weight. It preferably ranges from 240 to 420 parts by weight.
According to a specific embodiment, the alloy has any one of the following formula (in weight fraction): Au₅₈₃Ti₄₁₇R_z, Au₇₅₃Ti₂₄₇R_z or Au₈₀₄Ti₁₉₆R_z, wherein the amount z of grain refiner ranges from 30 to 200 ppm by weight of the total amount of gold and titanium.
According to a preferred embodiment of the invention, the alloy has a molar ratio gold/titanium of between 25.39/74.61 (14 carats) to 54.86/45.14 (20 carats), more preferably from 42.17/57.83 (18 carats, based on the weight of titanium and gold) to 54.86/45.14 (20 carats).
When x varies from 375 to 917, the amount of gold approximately ranges from 9 to 22 carats as compared to the total amount of gold and titanium.
The alloy may comprise impurities. In general, impurities may result from the metals used to form the alloy. Advantageously, these possible impurities amount to a total of less than 1000 ppm, more preferably, less than 500 ppm, more preferably less than 250 ppm, by weight of the alloy (x + y + z). The alloy may comprise a total amount of impurities of less than 100 ppm.
Accordingly, the alloy may comprise more impurities than grain refiner. The benefit resulting from the presence of a grain refiner is greater than any negative effect that might result from the presence of impurities, even when the amount of impurities exceeds that of grain refiner. Impurities do not affect the poor (or lack of) shape memory resulting from the presence of 30-200 ppm of grain refiner.
In particular, impurities can include any one or more of carbon, oxygen and nitrogen. In general, the amount of oxygen is greater than that of nitrogen, which is greater than that of carbon.
The total amount of one or more of carbon, oxygen and nitrogen is preferably less than 1000 ppm, more preferably, less than 500 ppm, more preferably less than 250 ppm, by weight of the alloy (x + y + z).
The total amount of impurities other than carbon, nitrogen and oxygen is preferably less than 500 ppm, more preferably less than 250 ppm, even more preferably less than 230 ppm, by weight of the alloy (x + y + z). These other impurities may include but not limited to hydrogen, sulfur; silicon; phosphorous; selenium; halogens; metals other than gold titanium and the grain refiner R; metalloids other than the grain refiner R.
In addition to a smaller grain size of the alloy, the grain refiner also contributes to the control of the precipitation step.
A smaller grain size reduces the macroscopic deformation of the alloy. As a result, the grain refiner also improves the ductility of the alloy as its ability to elongate increases as compared to alloys that comprise less than 30 ppm or more than 200 ppm of grain refiner.
The Au_xTi_yR_z alloy has a grain size that preferably ranges from 10 to 300 µm, more preferably from 20 to 200 µm.
The Au_xTi_yR_z alloy preferably comprises between 10 and 70 % by volume of Ti₃Au precipitates (Ti₃Au or Ti_42.17Au_57.83 by weight), more preferably between 20 and 60 %.
Ti₃Au precipitates actually improves the hardness of the alloy.
These Ti₃Au precipitates are dispersed within the Au_xTi_yR_z matrix. They are located at the interface between the grains i.e. at the grain boundary and/or within the matrix.
The alloy has a hardness that preferably ranges from 400 to 650 Hv, for instance from 450 to 500 Hv.
Due to its hardness properties, the alloy resists to scratches. In addition, the grain refiner, which prevents crack initiation, improves the aesthetic properties of the alloy.
The present invention also relates to a process for preparing the alloy of formula Au_xTi_yR_z. This process comprises the following steps:

1/ casting a material: melting x parts by weight of gold, y parts by weight of titanium and z ppm of a grain refiner selected from the group consisting of iridium, bore, vanadium, iron, cobalt, barium, yttrium, zirconium, and mixtures thereof,
wherein x = 375 to 917 parts by weight and y = 83 to 625 parts by weight,
and wherein x + y = 1000 and z = 30 to 200 ppm by weight of x + y,
2/ homogenizing the resulting material,
3/ optionally, deformation of the material from step 2/,
4/ optionally, precipitation by thermal treatment of the material from step 2/ or 3/ and obtaining an alloy of formula Au_xTi_yR_z.

The casting step consists in melting/solubilizing the Au, Ti and R elements at a temperature T_CAST that may be greater than that of the respective melting points of these elements (or mixtures thereof) and below that of their (or mixtures thereof) respective boiling points. For instance, casting gold, titanium and iridium may be carried out at a temperature of more than 2466°C (melting point of iridium) and less than 2856°C (boiling point of gold). The casting temperature T_CAST may be below the melting point of Ti or R. It is preferably above the melting point of gold. Melted gold can then solubilize titanium and/or the grain refiner R.
The casting step 1/ may include making a pre-alloy. Making a pre-alloy allows a lower casting temperature. The pre-alloying step is preferably carried out in an arc furnace.
When the process includes a pre-alloying step, the casting step may be carried out
The casting conditions (casting temperature and time) can be adjusted.
In general, pre-alloying or casting (without pre-alloying) the alloy, in particular in an arc furnace, is carried out at a temperature that preferably ranges from 2470 to 2850°C, more preferably from 2480 to 2700 °C. In that case, the different elements of the alloy are preferably maintained at this temperature for 5 seconds to 30 minutes, for instance for 5 seconds to 20 minutes. For instance, it can last from 5 seconds to 5 minutes, more preferably for 10 seconds to 2 minutes.
In general, casting the alloy, following a pre-alloying step, is carried out at a temperature of 1100 to 1500°C, more preferably from 1250 to 1450°C, in particular in an induction furnace or a cold crucible induction melting. In that case, the different elements of the alloy are preferably maintained at this temperature for 5min to 60min, for instance for 10min to 30min.
Casting the different elements of the alloy can consist in casting the appropriate amounts of elements by any means, for instance any one of: arc furnace, induction furnace, cold crucible induction melting...
In general, the casting step 1/ is followed by a cooling stage, for instance by air quenching or water quenching, preferably by water quenching.
The grain refiner may also act as seeding material for the Au_xTi_yR_z alloy as the material resulting from the casting step has an improved microstructure as compared to alloys consisting of gold and titanium. While thermal treatments increase the grain size, the grain refiner counterbalances this effect by slowing down the grain's growth.
According to a preferred embodiment, the homogenizing step 2/ is carried out at a temperature, T_HOM, of from 1200 to 1400°C, more preferably between 1250 and 1350°C.
The homogenizing step 2/ is preferably carried out for 2 hours to 12 hours, more preferably for 5 hours to 10 hours, for instance for 5 hours to 8 hours.
For instance, homogenizing step 2/ may be carried out between 1250 and 1350°C, for 5 hours to 10 hours.
The process preferably includes a cooling stage between steps 2/ and 3/. The homogenized material is preferably rapidly cooled, by air quenching or water quenching, more preferably by water quenching.
Deforming step 3/ is preferably carried out by cold compression or by rolling compression or by hot forging, more preferably by cold compression. The deformation is preferably comprised between 20 and 80%, more preferably between 30 and 70%.
The deforming step is preferably carried out at a temperature T_DEF of between 0 and 50°C, more preferably between 20 and 30°C.
Precipitation step 4/ is preferably carried out at a temperature T_PRE of from 400 to 1000°C, more preferably between 500°C and 700°C, for instance between 500°C and 600°C.
When the process includes deformation step 3/, precipitation step 4/ is preferably carried out for 10 minutes to 300 minutes, more preferably for 30 minutes to 180 minutes, for instance for 30 minutes to 120 minutes.
When the process does not include deformation step 3/, precipitation step 4/ is preferably carried out for 1 hour to 15 hours, more preferably for 2 hours to 12 hours.
For instance, after deformation step 3/, precipitation step 4/ may be carried out between 500°C and 600°C, for 30 minutes to 2 hours.
At the end of the precipitation step 4/, the alloy is cooled to room temperature (20 to 25°C), preferably by air quenching or water quenching, more preferably by water quenching.
The precipitation step 4/ promotes the formation of a Au_xTi_yR_z matrix comprising Ti₃Au precipitates, resulting in an improved hardness.
Applicant has noticed that step 2/ and/or step 4/ may increase the amount of oxygen impurity, which is preferably less than 1000 ppm.
At least one of steps 1/ to 4/ may be followed by a cooling stage to room temperature. Steps 1/ to 4/ are preferably followed by a cooling stage to room temperature, preferably by water quenching.
In general, T_CAST is greater than T_HOM, which is greater than T_DEF. On the other hand, T_PRE is generally greater than T_DEF but smaller than T_HOM.
The grain refiner affords smaller grain size. On the other hand, the deformation step and the precipitation step improve the hardness of the alloy.
The present invention also relates to an item comprising or consisting of the alloy of formula Au_xTi_yR_z. Accordingly, this alloy can be used in order to manufacture luxury goods.
For instance, it may be a watch component comprising (or consisting of) the alloy. It may be a jewel comprising (or consisting of) the alloy.
The item comprising or consisting of the alloy of formula Au_xTi_yR_z can be a jewel, a leather good, or a clothing accessory. It may also be a watch, a writing accessory, or a decorative item. For instance, it can be any of the followings: ring, ear ring, necklace, bracelet, pendant, watch or watch movement component (case, bezel, case back, crown, other case small parts, balance wheel, gear wheel, axis, screw...), buckle (belt, purse...), tie bar, cuff links, money clip, hair pin, pen, paper knife...
The alloy according to the invention can therefore be used in a field selected from the group consisting of: jewelry, horology, clothing, writing accessories, leather goods, and ornaments.
The invention and its advantages will become more apparent to one skilled in the art from the following figures and examples.

BRIEF DESCRIPTION OF THE DRAWINGS

Figures 1 and 2 show the grain size of Au_xTi_yIr_z alloys (x = 750, y = 250, z = 30-200 ppm).
Figure 3 shows Ti₃Au precipitates in Au₇₅₀Ti₂₅₀Ir_50ppm.
Figures 4 shows Au_xTi_yIr_z alloys (x = 750, y = 250, z = 30-200 ppm).
Figures 5 and 6 show Ti₃Au precipitates in Au₇₅₀Ti₂₅₀Ir_50ppm.
Figure 7 shows the recovered deformation of gold-titanium alloys (Au₇₅₀Ti₂₅₀ and Au₇₅₀Ti₂₅₀Ir_50ppm) after a cold deformation of 0-15%.
Figure 8 shows the grain size evolution of gold-titanium alloys (Au₇₅₀Ti₂₅₀ and Au₇₅₀Ti₂₅₀Ir_50ppm).

EXAMPLES

Alloys of formula Au_xTi_yR_z (x = 750 parts by weight, y = 250 parts by weight and z = 0 to 200 ppm by weight vs x+y) have been prepared following different experimental conditions, as outlined in Table 1. Samples "INV" refer to alloys according to the invention while samples "REF" are reference examples.
The process for preparing the different alloys comprises the following steps:

1/ Casting a material (samples 1-30): melting the appropriate amounts of gold, titanium and, eventually, iridium elements, for instance in an arc furnace, preferably between 2466°C and 2856°C.
2/ Homogenizing the resulting material (samples 6-30). This thermal treatment may be followed by a quenching step, preferably in water.
3/ Optionally, deformation by cold compression (samples 11-12 and 22-30).
4/ Optionally, precipitation by thermal treatment (samples 13-30). This thermal treatment may be followed by a quenching step (preferably in water).

Table 1: Experimental conditions for the preparation of Au _x Ti _y R _z alloys.

		Process
Sample (figure)	Alloy (Au_xTi_yR_z)	Hom	Def	PP	Hardness HV
1-REF	Au₇₅₀Ti₂₅₀	N	N	N	227
2-REF (fig. 1)	Au₇₅₀Ti₂₅₀Ir_30ppm	N	N	N	259
3-REF (fig. 1)	Au₇₅₀Ti₂₅₀Ir_50ppm	N	N	N	255
4-REF (fig. 1)	Au₇₅₀Ti₂₅₀Ir_100ppm	N	N	N	229
5-REF (fig. 1)	Au₇₅₀Ti₂₅₀Ir_200ppm	N	N	N	231
6-REF	Au₇₅₀Ti₂₅₀	Y^(wq)	N	N	224
7-INV (fig. 2)	Au₇₅₀Ti₂₅₀Ir_30ppm	Y^(wq)	N	N	237
8-INV (fig. 2-3)	Au₇₅₀Ti₂₅₀Ir_50ppm	Y^(wq)	N	N	227 (grain size 80µm)
9-INV (fig. 2)	Au₇₅₀Ti₂₅₀Ir_100ppm	Y^(wq)	N	N	236 (grain size 80µm)
10-INV (fig. 2)	Au₇₅₀Ti₂₅₀Ir_200ppm	Y^(wq)	N	N	241 (grain size 60µm)
11-REF	Au₇₅₀Ti₂₅₀	Y^(wq)	-31%	N	292
12-INV	Au₇₅₀Ti₂₅₀Ir_50ppm	Y^(wq)	-68%	N	446
13-REF	Au₇₅₀Ti₂₅₀	Y^(wq)	N	5 hours at 500°C^(wq)	231 (<1% Ti₃Au)
14-REF	AU₇₅₀Ti₂₅₀	Y^(wq)	N	10 hours at 700°C^(wq)	412 (33% Ti₃Au)
15-REF	Au₇₅₀Ti₂₅₀	Y^(wq)	N	10 hours at 750°C^(wq)	404 (31% Ti₃Au)
16-REF	Au₇₅₀Ti₂₅₀	Y^(wq)	N	10 hours at 1000°C^(wq)	315 (18% Ti₃Au)
17-INV (fig. 4)	Au₇₅₀Ti₂₅₀Ir_30ppm	Y^(wq)	N	10 hours at 750°C^(wq)	424
18-INV (fig. 4)	Au₇₅₀Ti₂₅₀Ir_50ppm	Y^(wq)	N	10 hours at 750°C^(wq)	404
19-INV (fig. 4)	Au₇₅₀Ti₂₅₀Ir100_ppm	Y^(wq)	N	10 hours at 750°C^(wq)	418
20-INV (fig. 4)	Au₇₅₀Ti₂₅₀Ir_200ppm	Y^(wq)	N	10 hours at 750°C^(wq)	407
21-INV	Au₇₅₀Ti₂₅₀Ir_50ppm	Y^(wq)	-68%	1 hour at 400°C^(wq)	505
22-INV	Au₇₅₀Ti₂₅₀Ir_50ppm	Y^(wq)	-69%	1 hour at 500°C^(wq)	609
23-INV (fig. 5)	A_U750Ti₂₅₀lr_50ppm	Y^(wq)	-68%	1 hour at 550°C^(wq)	584
24-INV	Au₇₅₀Ti₂₅₀Ir_50ppm	Y^(wq)	-68%	1 hour at 600°C^(wq)	532
25-INV (fig. 6)	Au₇₅₀Ti₂₅₀Ir_50ppm	Y^(wq)	-69%	1 hour at 700°C^(wq)	479

Y: Yes N: No ^(wq): water quenching
Horn: homogenization at 1310°C for 7 hours
Def: deformation by cold compression or by cold rolling (sample 25 only)
PP: thermal treatment for precipitation

Table 1 shows that, depending on the experimental conditions, the alloy according to the invention exhibits a hardness that can range from 227 to 609 Hv. The alloy hardness is improved when the process successively involves a homogenization step, a deformation step and a precipitation step. These steps are preferably following by a quenching step, for instance water quenching.
Figure 8 shows the grain size evolution of a sample after a homogenization step (1310°C for 7 hours). The presence of 50 ppm of a grain refiner (Ir) in Au₇₅₀Ti₂₅₀ affords smaller grains (less than 1 mm vs 2-3 mm).
The technical effect resulting from the presence of smaller grains is the reduction of macroscopic deformation that leads to crack initiation. In other words, the alloy according to the invention exhibits a more homogeneous deformation through the bulk, less segregation, and a better aesthetics since grains cannot be seen at a macroscopic scale.
However, figure 1 shows that the amount of grain refiner should be limited to 200 ppm in order to keep the smaller grain size benefit.
Additionally, since the grain refiner prevents crack initiation, it also improves the aesthetic properties of the alloy, especially after a polishing step. It improves the deformation of the alloy without generating cracks.
The homogenization step (samples 6-10) may be followed by a quenching step, preferably in water.
The deformation step, preferably by cold compression, improves the hardness of the alloy ( samples 11 and 12 vs samples 6 and 8).
The precipitation step is a thermal treatment, preferably at a temperature of at least 400°C and for 1 hour or more. This thermal treatment may be followed by a quenching step, preferably in water. It promotes the precipitation of Ti₃Au.
Ti₃Au precipitates improves the hardness of the alloy. As compared to Au₇₅₀Ti₂₅₀, the presence of 30-200 ppm of grain refiner promotes the Ti₃Au precipitation kinetics. In general, the deformation step (in the presence of a grain refiner or not) contribute to this phenomenon as well.
In the presence of a grain refiner (30-200 ppm), the above precipitation step 4/ promotes a mixed structure of Au-Ti and Ti₃Au. More specifically, the resulting alloy comprises Ti₃Au precipitates within a gold-titanium, or gold-titanium-grain refiner, matrix (figures 3-6).
Figure 7 shows the recovered deformation of different alloys (Au₇₅₀Ti₂₅₀ and Au₇₅₀Ti₂₅₀Ir_50ppm) after an incremental cold deformation of 0-15% and a mild heating step between 450°C and 700°C.
Prior to this test, steps "1/ + 2/" or steps "1/ + 2/ + 4/" have been applied to these samples. Step 2/ is a homogenizing step carried out at 1310°C for 7 hours while step 4/ is a precipitation step carried out at 750°C for 10 hours.
Above 10% deformation, the alloy according to the invention exhibits a recovered deformation of 2% or less vs 3% or more for Au₇₅₀Ti₂₅₀. This is a significant improvement of roughly 33%.
The recovered deformation relates to the difference between the size of a sample, following an incremental deformation stage (0-15%), and its final size after a mild heating step and the subsequent cooling stage. This incremental deformation is not the deformation of step 3/. The mild heating step following the incremental deformation is not a precipitation step 4/. This mild heating step allows change from martensitic phase to austenitic phase.
If upon cooling, the alloy recovers its initial size, it also loses the benefits of the mild heating step and means a return to its martensitic phase. Accordingly, it is highly beneficial to obtain a recovered deformation close to 0%, which results in an alloy that is easier to shape by mechanical deformation (stamping, cold rolling...) due to a reduced shape memory.

Claims

Alloy of formula Au_xTi_yR_z, wherein:
x = 375 to 917 parts by weight,

y = 83 to 625 parts by weight,

x + y = 1000 parts by weight,

z = 30 to 200 ppm by weight of x + y,

and wherein R is a grain refiner selected from the group consisting of iridium, bore, vanadium, iron, cobalt, barium, yttrium, zirconium, and mixtures thereof.
Alloy according to claim 1, characterized in that the grain refiner R is iridium.
Alloy according to any one of claims 1 to 2, characterized in that z ranges from 40 to 100 ppm.
Alloy according to any one of claims 1 to 3, characterized in that z ranges from 40 to 60 ppm, preferably z is equal to 50 ppm.
Alloy according to any one of claims 1 to 4, characterized in that:
x = 580 to 760 parts by weight,

y = 240 to 420 parts by weight.
Alloy according to claim 1 or 2, characterized in that the alloy has any one of the following formula, in weight fraction: Au₅₈₃Ti₄₁₇R_z, Au₇₅₃Ti₂₄₇R_z, or Au₈₀₄Ti₁₉₆R_z, wherein z ranges from 30 to 200 ppm by weight.
Process for preparing the alloy of formula Au_xTi_yR_z according to any one of claims 1 to 6, wherein the process comprises the following steps:
1/ casting a material: melting x parts by weight of gold, y parts by weight of titanium and z ppm of a grain refiner selected from the group consisting of iridium, bore, vanadium, iron, cobalt, barium, yttrium, zirconium, and mixtures thereof,
wherein x = 375 to 917 parts by weight and y = 83 to 625 parts by weight,
and wherein x + y = 1000 and z = 30 to 200 ppm by weight of x + y,

2/ homogenizing the resulting material by a thermal treatment,

3/ optionally, deforming the material from step 2/,

4/ optionally, precipitation by thermal treatment of the material step 2/ or 3/ and obtaining an alloy of formula Au_xTi_yR_z.
Process according to claim 7, characterized in that homogenizing step 2/ is carried out at a temperature of from 1200°C to 1400°C, for 2 hours to 12 hours, preferably between 1250°C and 1350°C for 5 hours to 10 hours.
Process according to claim 7 or 8, characterized in that deforming step 3/ is carried out by any one of: cold compression, hot forging, or rolling compression.
Process according to any one of claims 7 to 9, characterized in that precipitation step 4/ is carried out at a temperature of from 400°C to 1000°C, for 10 minutes to 300 minutes, preferably between 500°C and 700°C for 30 minutes to 180 minutes.
Process according to any one of claims 7 to 10, characterized in that each one of steps 1/ to 4/ is followed by a water quenching step.
Watch component comprising the alloy of any one of claims 1 to 6.
Watch component consisting of the alloy of any one of claims 1 to 6.
Jewel comprising the alloy of any one of claims 1 to 6.
Use of the alloy of any one of claims 1 to 6, in a field selected from the group consisting of: jewelry, horology, clothing, writing accessories, leather goods, and ornaments.