WO2006024928A1 - Procede de durcissement d'alliages metalliques - Google Patents

Procede de durcissement d'alliages metalliques Download PDF

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Publication number
WO2006024928A1
WO2006024928A1 PCT/IB2005/002580 IB2005002580W WO2006024928A1 WO 2006024928 A1 WO2006024928 A1 WO 2006024928A1 IB 2005002580 W IB2005002580 W IB 2005002580W WO 2006024928 A1 WO2006024928 A1 WO 2006024928A1
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WO
WIPO (PCT)
Prior art keywords
alloy
parent metal
item
platinum
solute
Prior art date
Application number
PCT/IB2005/002580
Other languages
English (en)
Inventor
Candace Irene Lang
Silethelwe Nxumalo
Original Assignee
University Of Cape Town
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by University Of Cape Town filed Critical University Of Cape Town
Priority to US11/661,448 priority Critical patent/US20080245449A1/en
Priority to EP05782474A priority patent/EP1797211A1/fr
Publication of WO2006024928A1 publication Critical patent/WO2006024928A1/fr

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
    • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
    • C22F1/16—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of other metals or alloys based thereon
    • C22F1/18—High-melting or refractory metals or alloys based thereon
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C5/00—Alloys based on noble metals
    • C22C5/04—Alloys based on a platinum group metal
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
    • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
    • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
    • C22F1/14—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of noble metals or alloys based thereon

Definitions

  • This invention relates to alloy metals.
  • this invention relates to a method of rendering an alloy metal with increased hardness.
  • the invention has particular relevance to platinum alloys and hardening of low-solute platinum alloys by heat treatment.
  • T n * is material dependent but is usually approximately 1000 degrees Centigrade (deg C) for common platinum jewellery alloys, although this figure can vary by several hundred degrees depending on the material.
  • cold working is inherent in hand-working jewellery manufacturing processes. As such, cold working includes rolling, drawing, etc of the alloy material.
  • cold worked platinum 5 wt.% tungsten can have a HV of
  • age-hardening or precipitation hardening which increases hardness by solid-state precipitation of a second phase. This process involves:
  • a method of rendering an alloy with increased hardness including the steps of heat treating the alloy until the formation of at least one ordered region in the alloy, wherein the alloy is not a PtCr alloy.
  • increased hardness refers to the comparison of the alloy including ordered regions and that alloy not including ordered regions.
  • 'increased hardness' is intended to encompass rendering an alloy with a hardness not predictable or obtainable using conventional hardening mechanisms.
  • the term 'ordered region' is intended to mean the existence of a super-lattice structure, in which the location of different atomic species is periodic and predictable.
  • the ordered region is an X 8 Y ordered region within the alloy wherein X is a parent metal and Y is the solute atom type.
  • the parent metal is preferably platinum (Pt).
  • Pt platinum
  • other metals such as palladium (Pd) and nickel (Ni) are also considered to fall within the ambit of the present invention.
  • Pd alloys like Pt alloys, find particular application in jewellery applications and Ni has application in high temperature and other applications.
  • the solute atom is a transition metal element.
  • the solute atom may be selected from Ti, V, Zr, Cr (where the parent metal is not Pt), Nb, Mo, Hf, Ta and W.
  • the metal alloy may be a binary alloy, i.e. comprising the parent metal and one other solute atom, or it may be a ternary alloy, i.e. comprising the parent metal and two solute atoms. It will be appreciated that quaternary and other alloys are also contemplated to lie within the ambit of the present invention.
  • the alloy preferably includes at least 85wt.% parent metal, more preferably at least 90wt.%, more preferably at least 95wt.% parent metal.
  • the solute atoms may be present in not more than 15wt.% more preferably not more than 10wt.%, more preferably not more than 5wt.%
  • the alloy comprises 95wt.% of the parent metal, 0.01 to 4.99wt.% of a first solute atom, the balance of the alloy comprising at least one further solute atom selected to enhance predetermined criteria of the alloy.
  • the parent metal is Pt and the solute atom is V.
  • the alloy preferably contains more than 94 wt.% Pt, more preferably more than 95 wt.% Pt, preferably more than 96 wt.% Pt, most preferably more than 96.5wt.% Pt.
  • the alloy may contain less than 99.99wt.% Pt, preferably less than 98wt.% Pt, preferably less than 97wt.% Pt, more preferably less than 96wt.% Pt.
  • the alloy preferably contains less than 6wt.% V, more preferably less than 5wt.% V, more preferably less than 4wt.% V, most preferably less than 3.5wt.% V.
  • the alloy may contain more than 0.01wt.% V, more preferably more than 1wt.% V, more preferably more than 2wt.% V, more preferably more than 3wt.% V.
  • the alloy comprises 95wt.% Pt, 3.2wt.% V, the balance being selected from the group of transition metals set out above.
  • the alloy is heated to below its recrystallisation temperature (T 1x ).
  • the alloy is preferably cooled to ambient temperature following heating.
  • the alloy is preferably heated to below the order/disorder temperature (T c )of the alloy to induce ordering. It will be appreciated that a given alloy may present one of two scenarios according to the present invention:
  • T c is below the recrystallisation temperature T 1x - in which case heating below T 0 means heating below T 1 *.
  • T 0 is above J n - in which case it may be required to heat above J n to induce ordering.
  • heating above J n may negate the effect of any prior cold work with the result that there may be a reduced nett hardening effect.
  • T c is above J n the alloy is heated below J n (which is below T c ).
  • the method may include the step of initially cold working the alloy to a predetermined degree of deformation/strain. In this manner it is possible to achieve a particular hardness prior to heating the alloy as hereinbefore described. This may be achieved by cold working the alloy for a pre-determined period of time at a pre-determined strain rate.
  • the subsequent heat treatment is preferably effected in a furnace.
  • an alloy comprising a parent metal selected from Pt, Pd and Ni and a solute atom wherein the alloy has a Vickers Hardness Value of more than 370, preferably more than 400, more preferably more than 420, more preferably more than 440, more preferably more than 450, more preferably more than 470, more preferably more than 490, most preferably more than 500.
  • an item fashioned or including an alloy as hereinbefore described and/or prepared as hereinbefore described.
  • an alloy including an ordered region and/or as hereinbefore described in the preparation of an item.
  • the item may be an item of jewellery, cutlery or other valuable.
  • the hard alloys according to the present invention are achieved by the formation of ordered regions within the metal alloy, Ordered regions' meaning the existence of a super-lattice structure, in which the location of different atomic species is periodic and predictable, rather than simply being a random solid solution of different atomic types.
  • the preferred type of ordered region has the stoichiometry X 8 Y, where X is the parent metal and Y is the solute atom type.
  • a preferred alloy is a platinum alloy and Pt 8 X is believed to exist in the following alloys set out below.
  • Other preferred alloys include palladium and nickel alloys and the same stoichiometry also exists in these alloys. This has been predicted from first thermodynamic principles known in the art [AJ. Ardell, Metallic alloys: Experimental and theoretical perspectives, 93-102 (1994). Z.W. Lu and B.M. Klein, Phys. Rev. B 50, 5962-5970 (1994)].
  • PtTi the Pt 8 Ti structure has been predicted, observed, and reported in the open literature.
  • PtV the Pt 8 V structure has been predicted, observed and reported in the open literature D. Schryvers, J. Van Landuyt and S. Amelinckx, Mat. Res. Bull, 18, 1369 (1983).
  • PtZr the Pt 8 Zr structure has been predicted, observed and reported in the open literature.
  • PtCr The Pt 8 Cr structure has been predicted and was observed by the applicant.
  • PtNb the Pt 8 Nb structure has been predicted, but not yet observed.
  • PtMo the Pt 8 Mo structure has been predicted, but not yet observed.
  • PtHf, PtTa, PtW the Pt 8 Hf , Pt 8 Ta and Pt 8 W structures have been predicted, but not yet observed.
  • the formation of the Pt 8 X structure confers an impressive increase in hardness to an alloy - something that has not previously been observed.
  • a HV of over 500 is achieved. This is a significant value compared to the HV of cold-worked stainless steel at 400.
  • the above HV of over 500 is particularly surprising considering the HV of the annealed 3.2%.wt PtV alloy is approximately 210 and the HV of the cold worked alloy is approximately 360. (Annealing is heat treatment designed to negate the effect of cold working.)
  • the alloys according to the present invention must be heat treated to produce the Pt 8 X structure. There are several important practical considerations here:
  • the method comprises only a single heat treatment, of as short a duration as 15 minutes. No further change in hardness is observed following heat treatments of up to 2500 hours.
  • precipitation hardening which produces the next highest hardening in jewellery alloys, requires two heat treatments, possibly lengthy.
  • Figure 1 is a graph of hardness vs. heat treatment temperature for platinum 3.2 wt.% vanadium alloy heat treated for three hours.
  • Figure 2 is a graph of hardness vs. time for platinum 3.2 wt.% vanadium alloy heat treated at 400 deg C.
  • Figure 3 is a graph of hardness vs. heat treatment temperature for platinum 2.9 wt.% chromium alloy heat treated for three hours.
  • Figure 4 is a graph of hardness vs. time for platinum 2.9 wt.% chromium heat treated at 300 deg C.
  • Figure 5 is a graph of hardness vs. heat treatment temperature for platinum 5.2 wt.% molybdenum heat treated for three hours.
  • the platinum alloy is cast and homogenised to provide an alloy having a uniform structure.
  • the term 'uniform structure' refers to compositional homogeneity and an equiaxed grain structure.
  • the platinum alloy is then cold worked to produce the jewellery item by a process of rolling, drawing or any other suitable means of working, resulting in a HV of approximately HVi OOg 366.
  • the jewellery item is then heat treated in a furnace at a temperature below 600 0 C for three hours, followed by cooling to room temperature.
  • the jewellery item After the heat treatment the jewellery item has an enhanced HV of approximately 500 which is higher than the HV that can be attained by cold working, i.e. approximately 360.
  • the platinum/chromium alloy is cast and homogenised to provide an alloy having a uniform structure.
  • the platinum alloy is then cold worked to produce the jewellery item by a process of rolling, drawing or any other suitable means of working, resulting in a HV of approximately HV 1OOg 295.
  • the jewellery item is then heat treated in a furnace at a temperature below 600°C for three hours, followed by cooling to room temperature.
  • the jewellery item After the heat treatment the jewellery item has an enhanced HV of approximately 330 which is higher than the HV that can be attained by cold working, i.e. approximately 295.
  • the platinum/molybdenum alloy is cast and homogenised to provide an alloy having a uniform structure.
  • the platinum alloy is then cold worked to produce the jewellery item by a process of rolling, drawing or any other suitable means of working, resulting in a HV of approximately HVi 0 o g 360.
  • the jewellery item is then heat treated in a furnace at a temperature below 600 0 C for three hours, followed by cooling to room temperature.
  • the jewellery item After the heat treatment the jewellery item has an enhanced HV of over 400 which is higher than the HV that can be attained by cold working, i.e. approximately 360.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Adornments (AREA)

Abstract

L'invention concerne un procédé pouvant renforcer la dureté d'un alliage. Le procédé consiste à: thermotraiter l'alliage jusqu'à l'obtention d'au moins une zone ordonnée dans l'alliage. L'invention concerne en outre un alliage préparé selon ledit procédé et un article de joaillerie réalisé à partir de l'alliage ou comprenant l'alliage.
PCT/IB2005/002580 2004-09-02 2005-09-01 Procede de durcissement d'alliages metalliques WO2006024928A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
US11/661,448 US20080245449A1 (en) 2004-09-02 2005-09-01 Hardening of Metal Alloys
EP05782474A EP1797211A1 (fr) 2004-09-02 2005-09-01 Procede de durcissement d'alliages metalliques

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
ZA200406994 2004-09-02
ZA2004/6994 2004-09-02

Publications (1)

Publication Number Publication Date
WO2006024928A1 true WO2006024928A1 (fr) 2006-03-09

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ID=35229711

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Application Number Title Priority Date Filing Date
PCT/IB2005/002580 WO2006024928A1 (fr) 2004-09-02 2005-09-01 Procede de durcissement d'alliages metalliques

Country Status (4)

Country Link
US (1) US20080245449A1 (fr)
EP (1) EP1797211A1 (fr)
WO (1) WO2006024928A1 (fr)
ZA (1) ZA200703477B (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3121297A1 (fr) * 2015-07-23 2017-01-25 Cartier International AG Procédé d'obtention d'un composant d'ornement en alliage de platine

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3020835B1 (fr) * 2014-11-17 2021-04-21 Omega SA Pièce d'horlogerie, de bijouterie ou de joaillerie comportant un composant réalisé dans un alliage à base de palladium

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1477962A (en) * 1976-05-11 1977-06-29 Engelhard Ind Ltd Fastening member for platinum jewellery
JPS57169041A (en) * 1981-04-11 1982-10-18 Tanaka Kikinzoku Kogyo Kk Platinum alloy for accessory
JPS63262434A (ja) * 1987-04-15 1988-10-28 デグツサ・アクチエンゲゼルシヤフト 弾性を有する装身具用白金合金
JPH0243331A (ja) * 1988-08-02 1990-02-13 Tokuriki Honten Co Ltd 装飾用白金合金
WO1997040200A1 (fr) * 1996-04-24 1997-10-30 Mintek Alliage de platine

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KR940004986B1 (ko) * 1984-08-27 1994-06-09 가부시기가이샤 히다찌세이사꾸쇼 자성막의 제조방법 및 그것을 사용한 자기헤드
US5188679A (en) * 1990-07-19 1993-02-23 Kretchmer Steven D Metal compression-spring gemstone mountings
US5811182A (en) * 1991-10-04 1998-09-22 Tulip Memory Systems, Inc. Magnetic recording medium having a substrate and a titanium nitride underlayer
US5793600A (en) * 1994-05-16 1998-08-11 Texas Instruments Incorporated Method for forming high dielectric capacitor electrode structure and semiconductor memory devices
US5869195A (en) * 1997-01-03 1999-02-09 Exxon Research And Engineering Company Corrosion resistant carbon steel
JP3960069B2 (ja) * 2002-02-13 2007-08-15 住友金属工業株式会社 Ｎｉ基合金管の熱処理方法

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1477962A (en) * 1976-05-11 1977-06-29 Engelhard Ind Ltd Fastening member for platinum jewellery
JPS57169041A (en) * 1981-04-11 1982-10-18 Tanaka Kikinzoku Kogyo Kk Platinum alloy for accessory
JPS63262434A (ja) * 1987-04-15 1988-10-28 デグツサ・アクチエンゲゼルシヤフト 弾性を有する装身具用白金合金
JPH0243331A (ja) * 1988-08-02 1990-02-13 Tokuriki Honten Co Ltd 装飾用白金合金
WO1997040200A1 (fr) * 1996-04-24 1997-10-30 Mintek Alliage de platine

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 007, no. 011 (C - 145) 18 January 1983 (1983-01-18) *
PATENT ABSTRACTS OF JAPAN vol. 014, no. 202 (C - 0713) 25 April 1990 (1990-04-25) *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3121297A1 (fr) * 2015-07-23 2017-01-25 Cartier International AG Procédé d'obtention d'un composant d'ornement en alliage de platine

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EP1797211A1 (fr) 2007-06-20
ZA200703477B (en) 2008-08-27
US20080245449A1 (en) 2008-10-09

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