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The age hardenability of 22 karat gold (Au-5.8wt.%Cu-2.5wt.%Ag) alloyed with titanium


The age hardenability of 22 karat gold (Au-5.8wt.%Cu-2.5wt.%Ag) alloyed with Ti at various concentrations (0.5, 0.75, and 1 wt.%) was studied. The addition level of Ti is compensated with Ag to maintain the purity of gold in 22 karat, i.e., 91.75 wt.%. The Ti containing 22 karat gold was prepared by melting Au, Cu, and Ag and adding Ti via Au-6wt.%Ti master alloy. The castings obtained were cold-rolled into thin sheet (90% reduction). Both the cast and cold-rolled sheets were subjected to age hardening treatment (solutionizing and artificial aging). Artificial aging was performed as a function of time at 550 °C to identify the peak aging. At all addition level of Ti, the 22 karat gold responded well to the age hardening treatment. The cold-worked sheet samples showed faster peak aging within 30 min. and higher peak hardness than their cast counterpart. Increasing the Ti concentration increases the peak hardness of both cold-rolled sheet and casting samples. Transmission electron microscopic analysis of the peak aged cold-rolled sheet samples shows uniformly distributed coherent Au4Ti precipitates in Au matrix which contribute to the higher hardness.

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  1. Saradesh KM, Vinodkumar GS (2020) Grain refinement of 24 karat gold (99.99 wt.% pure) and 22 karat gold (Au-5.8 wt.% Cu-2.5 wt.% Ag) by Au-6wt.% Ti grain refiner. Gold Bull 53:19–29.

    CAS  Article  Google Scholar 

  2. Corti CW (1999) Metallurgy of microalloyed 24 carat golds. Gold Bull 32:39–47.

    CAS  Article  Google Scholar 

  3. Gafner G (1989) The development of 990 gold—titanium: its production, use and properties. Gold Bull 22:112–122.

    CAS  Article  Google Scholar 

  4. du Toit M, van der Lingen E, Glaner L, Süss R (2002) The development of a novel gold alloy with 995 fineness and increased hardness. Gold Bull 35:46–52.

    Article  Google Scholar 

  5. Ning Y (2005) Properties and applications of some gold alloys modified by rare earth additions. Gold Bull 38:3–8.

    CAS  Article  Google Scholar 

  6. Fischer J (2000) Mechanical, thermal, and chemical analyses of the binary system Au-Ti in the development of a dental alloy. J Bio Mater Res 52:678–686.;2-P

    CAS  Article  Google Scholar 

  7. Takada Y, Ito M, Kimura K, Okuno O (2005) Electrochemical properties and released ions of Au-1.6 mass% Ti alloy. Dent Mater J 24:153162.

    Article  Google Scholar 

  8. Humpston G, Jacobson DM (1992) A new high strength gold bond wire. Gold Bull 25:132–145.

    CAS  Article  Google Scholar 

  9. Jacobson DM, Harrison MR, Sangha SP (1996) Stable strengthening of 990 gold. Gold Bull 29:95–100.

    CAS  Article  Google Scholar 

  10. Fischer-Bühner J (2005) Hardening of low-alloyed gold. Gold Bull 38:120–131.

    Article  Google Scholar 

  11. Taylor AD (2002) 22k Gold alloy compositions. International Patent publication no. WO 02/18664 A1

  12. Cretu C, Van Der Lingen E, Glaner L (2004) Hard 22 carat gold alloys. World gold council-Vicenza.

  13. Yoshihisa Y, Shimizu T (2012) Metal allergy and systemic contact dermatitis: an overview. Dermatol Res Practice 12:1–5.

    Article  Google Scholar 

  14. Cretu C, Van Der Lingen E (1999) Coloured gold alloys. Gold Bull 32:115–126.

    CAS  Article  Google Scholar 

  15. Saradesh KM, Vinodkumar GS (2020) Metallurgical processes for hardening of 22Karat Gold for light weight and high strength jewelry manufacturing. J Mater Res and Tech 9:2009–2020.

    CAS  Article  Google Scholar 

  16. Murray JL (1983) The Au-Ti (gold-titanium) system. Bull Alloy Phase Diagram 4:278–283.

    Article  Google Scholar 

  17. Kubota M, Nie JF, Muddle BC (2004) Characterisation of precipitation hardening response and as-quenched microstructures in Al-Mg (-Ag) alloys. Mater trans 45:3256–3263.

    CAS  Article  Google Scholar 

  18. D’Brass S, Ravi KR, Nampoothiri J, Saradesh KM, Rajasekaran T, Vinodkumar GS (2019) The effect of melt ultrasound treatment on the microstructure and age hardenability of Al-4 Wt Pct Cu/TiC composite. Metall Mater Trans B 50:2557–2565.

    CAS  Article  Google Scholar 

  19. Iwamura S, Ozeki Y, Yoshida H (2010) Effects of natural aging and cold work on the strength of 2013 aluminum alloy. J Jpn Inst Light Met 60:220–224.

    CAS  Article  Google Scholar 

  20. Davis JR (2001) Copper and copper alloys. ASM International, Materials Park, OH 44073-0002, p. 66

  21. Kim HII, Seol HJ, Bae DH, Shim JY, Takada Y, Okuno O (1999) Isothermal age-hardening behaviour in a Au-1.6 wt% Ti alloy. Dent Mater J 18:32–41.

  22. Villars P, Prince A, Okamoto H (1995) Handbook of tertiary alloy phase diagrams, vol 1. ASM International, Materials Park, OH 44073-0002, pp 260–261

  23. Koster W (1960) Das Zweistoffsystem gold-vanadium. Z Metallkde 51:501–502

    CAS  Google Scholar 

  24. Wachtel E, Vetter U (1961) Magnetische Untersuchungen an Gold-Chrom-Legierungen. Z Metallkde 52:525–529

    CAS  Google Scholar 

  25. Takahashi T, Kikuchi M, Takada Y, Okuno O (1998) Basic compositions of gold titanium alloys for dental casting. JJ Dent Mater 17:126–139

    CAS  Google Scholar 

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The authors wish to thank, Mr. S. Santhosh and Mr. Sanjay Ranawade of Titan Company Ltd (Jewelry Division), Hosur, Tamilnadu, India, for supporting this work by supplying 24 karat gold (99.99wt.% pure).

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Correspondence to G. S. Vinodkumar.

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Saradesh, K.M., Ravi, K.R. & Vinodkumar, G.S. The age hardenability of 22 karat gold (Au-5.8wt.%Cu-2.5wt.%Ag) alloyed with titanium. Gold Bull 54, 105–113 (2021).

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  • 22 karat gold
  • Titanium
  • Age hardening
  • Au-Ti equilibrium diagram
  • Au4Ti intermetallic