• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The present invention relates to an article of jewelery, watchmaking or leather goods comprising at least a part in a shape memory alloy comprising gold. The shape memory alloy is titrated to at least 18 carats and has the following atomic percentage composition: 46 to 55at% gold, 38 to 47at% titanium, 0.1 to 15at% zirconium, 0 to 5at % of niobium.
    公开号:CH715040A2
    申请号:CH6392019
    申请日:2019-05-16
    公开日:2019-11-29
    发明作者:Colas Damien；Diologent Frédéric；Chalon Faivre
    申请人:Richemont Int Sa；
    IPC主号:
    专利说明:

    Description: The present invention relates to a piece of jewelry, watchmaking or leather goods comprising at least one part in a shape memory alloy.
    A shape memory alloy (AMF) is a metal alloy with several properties: the ability to keep in memory an initial shape and to find it even after a deformation (one-way memory effect) or the possibility of alternating between two shapes previously memorized when its temperature varies around a critical temperature (two-way memory effect), and a superelastic behavior allowing elongations without permanent deformation greater than those of other metals. Among the best known and used shape memory alloys, there is a whole family of nickel and titanium alloys (NiTi).
    The characteristics of AMF come from the fact that these alloys have two crystallographic phases called martensitic phase and austenitic phase (by analogy to steels, although the transformation is time independent in the case of AMF). The transition from one phase to another is done either by temperature change, or by application of a constraint. The advantage of AMF is that the phase transformation is displacive (small global and homogeneous displacements of atoms, therefore no change even local to the chemical composition) rather than diffusive. Any pseudo plastic deformation applied in the martensitic phase will lead to the reorientation of the martensite variants (deformation below the elastic limit). By heating to regain the austenitic phase, the alloy regains its initial shape.
    The following transition temperatures are defined:
    - Ms and Mf, the temperatures at which the martensitic phase transition begins and ends respectively when the alloy is cooled;
    - As and Af, the temperatures at which the transition from martensitic phase to austenitic phase begins and ends respectively when the alloy is heated.
    As indicated above, certain shape memory alloys have a one-way memory effect: the alloy is capable of returning to its initial shape by heating after mechanical deformation.
    The principle of the one-way memory effect is as follows (see the graphs in FIGS. 1 and 2):
    a) The alloy in its initial form is cooled without constraint starting from a temperature Ti which is higher than Ms, and this up to a temperature Tf lower than Mf. Martensite is therefore formed but the transformation deformation is zero.
    b) A stress (charge and discharge) is applied at constant temperature (Tf) to deform the alloy in a second form. There is no phase transformation, but reorientation of the martensite variants formed during cooling in step (a). It is important to note that this applied stress must not exceed the elastic limit. The deformation during this stage is pseudoplastic.
    c) The alloy is heated to a temperature Ti greater than Af under zero stress. There is a phase change (martensite turns into austenite) and the alloy returns to its original shape.
    The properties of shape memory alloys can be used to make jewelry, watchmaking or leather goods, the shape of which can be modified by constraint and / or temperature change, either for practical reasons (shaping , crimping, repair of accidental deformation) or for aesthetic and playful reasons. For example, EP 1 238 600 describes articles of jewelry made of AMF whose shape changes at temperatures close to that of the human body (wearing temperature). That is to say that the alloys chosen have transition temperatures, and in particular a temperature Af, between 20 ° C and 35 ° C. Such a jewel will therefore change shape when worn (heated by the wearer, heated under a jacket, cooled in the open air or soaked in cold water) for a playful, aesthetic or even practical aspect (easy donning of a bracelet which tightens once worn thanks to the body heat of the wearer).
    Document JP 2014 152 355 seeks to obtain a shape memory alloy based on gold and titanium having high transition temperatures (between 300 ° C. to 600 ° C.) in particular for use in the automotive fields. and aeronautics that require parts that must withstand high temperatures. The following composition in atomic percentage is especially described there: 48 to 52at% of titanium; 0.1 to 22at% of one or more of the following: Zr, Nb, Hf, Ta, V, Mo and W; 26 to 51.9at% gold. Although containing gold, this document does not seek to obtain an alloy with a title greater than or equal to 18 carats.
    The document EP 3 040 790 describes a piece of jewelry made of light precious alloy based on titanium. It is noted there that the TiPd and TiAu alloys are titratable and particularly light. The document is concerned with the replacement of palladium in these titanium-based alloys. More particularly, it is proposed to obtain a ductile alloy based on the equi-atomic intermetallic TiPd in which the excess of palladium relative to the mass titer Pd500 is partially or completely replaced by a non-precious element so that titanium always represents 50 atomic% of
    CH 715 040 A2 the final alloy. This document does not give any indication with regard to obtaining titanium and gold alloys which could be titratable to 18 carats (750). In addition, the shape memory effects of these alloys are here considered parasitic and are therefore not sought.
    The object of the present invention is to produce an article of jewelry, timepieces or leather goods comprising a part in an AMF alloy, the composition of which mainly comprises gold, preferably in large enough quantities to be titrated to 18 carats at least.
    The present invention relates to a piece of jewelry, watches or leather goods according to claim 1. The accompanying figures serve to illustrate the description of the invention.
    Figs. 1 and 2 illustrate graphically the principle of the one-way memory effect of MFAs.
    Figs. 3 to 5 represent a deformation curve for different gold-based AMF alloys according to the present invention.
    The invention therefore relates to an article of jewelry, timepieces or leather goods comprising at least one part made of a shape memory alloy, the composition of which mainly comprises gold and in particular has a higher content or equal to 18 carats. More precisely, according to the invention, the deformation memory alloy has the following composition given in atomic percentage:
    55% gold, 47% titanium,
    0.1 to 15%% zirconium, 5%% niobium.
    Preferably, the atomic percentage of gold is between 48 and 54% at, even more preferably between 50 and 52% at.
    Preferably, the atomic percentage of titanium is between 40 and 47% at.
    Preferably, the atomic percentage of zirconium is between 0.5 and 12% at, even more preferably between 1 and 10% at.
    In a preferred manner, the following compositions are considered (in atomic percentage): 50Au40Ti10Zr, 50Au45Ti3Zr2Nb and 52Au47Ti1Zr.
    As an exemplary embodiment, there may be mentioned a ring of which at least part of the ring or the entire ring is made of an alloy as above or even a watch strap with a rigid link. In these two examples, the properties of the shape memory alloy can be used to vary the size of the article or to easily correct accidental deformation.
    The development of the alloy is described below. The first step is to prepare the pure elements used in the composition of the shape memory alloy. The elements are then melted together in an arc furnace, the temperature of which reaches at least 1854.7 ° C in the case of an alloy based on gold (melting point Tf (Au) = 1064 ° C), of titanium (point Tf (Ti) = 1668 ° C) and zirconium (melting point Tf (Zr) = 1854.7 ° C). Before melting, a secondary vacuum of the order of 7 χ 10 -5 mbar is drawn and argon is injected. The stock is cooled in the form of ingot or rod for example and can then be machined using conventional machining techniques. Finally, a homogenization treatment is carried out by maintaining the part at 850-900 ° C for one hour under argon, by carrying out a first quenching with water and again maintaining the part at 300 ° C under argon for thirty minutes before re-quenching with water.
    In theory, the possibilities of deformation S (%) recovered when heating AMF alloys reach 6 to 8%. The practical results for the gold-based AMF alloys according to the invention reach 3 to 6%.
    Figs. 3 to 5 illustrate the deformation curves for the following alloys 50Au40Ti10Zr, 52Au47Ti1Zr and 50Au45Ti3Zr2Nb respectively.
    These curves were obtained during compression tests carried out on pins 3mm in diameter by 4.5mm in height developed according to the above technique and according to the following test protocol:
    Compression at 8.5% at constant temperature, martensitic phase alloy;
    Relaxation of the constraint;
    CH 715 040 A2
    Measurement of the deformation S at the end of compression;
    Heating at a temperature above Af, here between 550-600 ° C for 1 minute;
    Measurement of the residual strain S.
    The results obtained for the 50Au40Ti10Zr, 52Au47Ti1Zr and 50Au45Ti3Zr2Nb alloys are given in the table below and illustrated in FIGS. 3 to 5:
    Alloy ε (%) end of compression ε (%) recovered on heating ε (%) residual AMF ratio (%) 50Au40Tï10Zr 5.7 4.4 1.3 77 52Au47Ti1Zr 6.4 3.7 2.7 58 50Au45Ti3Zr2Nb 6.3 5 1.3 80
    The AMF ratio is defined as the ratio between the deformation S recovered on heating and the deformation S at the end of compression. Preferably, the shape memory alloy is chosen to have an AMF ratio greater than 50%.
    Particular elements such as Ta, Sn, Cr, Co, Mo, Y, Pd and Ag could be added to the shape memory alloy according to the invention in order to maximize the AMF ratio and / or to influence the transition temperatures.
    The present invention thus makes it possible to produce an article of jewelry, timepieces or leather goods in precious metal, since the gold-based alloy can be titrated to at least 18 carats. The properties of the shape memory alloy allow a wide variety of applications: playful, aesthetic or practical (change of size or repair of accidental deformation). The absence of nickel makes it a safe alloy for the wearer.
    权利要求:
    Claims (8)
    [1]
    claims
    1. An article of jewelry, timepieces or leather goods comprising at least one part in a shape memory alloy comprising gold, characterized in that the shape memory alloy is titrated to at least 18 carats and has the following composition in atomic percentage:
    - 46 to 55at% gold,
    - 38 to 47at% of titanium,
    -0.1 to 15at% of zirconium,
    - 0 to 5at% niobium.
    [2]
    2. Article according to claim 1, characterized in that said shape memory alloy has an atomic percentage of niobium of 0.1 to 5 at.
    [3]
    3. Article according to one of the preceding claims, characterized in that said shape memory alloy has an atomic percentage of gold of between 48 and 54% at, preferably between 50 and 52% at.
    [4]
    4. Article according to one of the preceding claims, characterized in that said shape memory alloy has an atomic percentage of titanium of between 40 and 47% at.
    [5]
    5. Article according to one of the preceding claims, characterized in that said shape memory alloy has an atomic percentage of zirconium of between 0.5 and 12% at, preferably between 1 and 10% at.
    [6]
    6. Article according to one of the preceding claims, characterized in that the AMF ratio of the shape memory alloy, defined as being the ratio between the deformation S recovered during the heating of the alloy to a temperature higher than the temperature (Af) at the end of transition from martensitic phase to austenitic phase and the deformation S after application of a stress when the alloy is in martensitic phase, is greater than 50%.
    [7]
    7. Article according to the preceding claim, characterized in that the AMF ratio of the shape memory alloy is greater than 70%.
    [8]
    8. Article according to one of the preceding claims, characterized in that the shape memory alloy has one of the following compositions given in atomic percentage 50Au40Ti10Zr, 50Au45Ti3Zr2Nb or 52Au47Ti1Zr.
    CH 715 040 A2
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    同族专利:
    公开号 | 公开日
    CH715040A8|2020-02-14|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    法律状态:
    2019-12-13| PK| Correction|Free format text: RECTIFICATION INVENTEUR |
    2020-02-14| PK| Correction|Free format text: RECTIFICATION A8 |
    优先权:
    申请号 | 申请日 | 专利标题
    CH6512018|2018-05-24|
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