title: Properties of experimental copper-aluminium-nickel alloys for dental post-and-core applications.
abstract: OBJECTIVE
  This study aimed to develop a copper-aluminium-nickel alloy which has properties comparable to that of dental alloys used for dental post and core applications with the reasonable cost.
  
  
  METHODS
  Sixteen groups of experimental copper alloys with variants of 3, 6, 9, 12 wt% Al and 0, 2, 4, 6 wt% Ni were prepared and casted. Their properties were tested and evaluated. The data of thermal, physical, and mechanical properties were analyzed using the two-way ANOVA and Tukey's test (α=0.05). The alloy toxicity was evaluated according to the ISO standard.
  
  
  RESULTS
  The solidus and liquidus points of experimental alloys ranged from 1023℃ to 1113℃ and increased as the nickel content increased. The highest ultimate tensile strength (595.9 ± 14.2 MPa) was shown in the Cu-12Al-4Ni alloy. The tensile strength was increased as the both elements increased. Alloys with 3-6 wt% Al exhibited a small amount of 0.2% proof strength. Accordingly, the Cu-9Al-2Ni and Cu-9Al-4Ni alloys not only demonstrated an appropriate modulus of elasticity (113.9 ± 8.0 and 122.8 ± 11.3 GPa, respectively), but also had a value of 0.2% proof strength (190.8 ± 4.8 and 198.2 ± 3.4 MPa, respectively), which complied with the ISO standard requirement (>180 MPa). Alloys with the highest contents of nickel (6 wt% Ni) revealed a widespread decolourisation zone (5.0-5.9 mm), which correspondingly produced the largest cell response, equating positive control.
  
  
  CONCLUSIONS
  The copper alloys fused with 9 wt% Al and 2-4 wt% Ni can be considered for a potential use as dental post and core applications.
authors.affiliation: Dental Biomaterials Program, Faculty of Dentistry, Mahidol University, Yothi Road, Rajthevee, Bangkok, Thailand.
authors.forename: Apiwat
authors.initials: A
authors.lastname: Rittapai
authors.affiliation: Department of Prosthodontics, Faculty of Dentistry, Mahidol University, Yothi Road, Rajthevee, Bangkok, Thailand.
authors.forename: Somchai
authors.initials: S
authors.lastname: Urapepon
authors.affiliation: National Metal and Materials Technology Center (MTEC), Phahonyothin Road, Khlong Luang, Pathum Thani, Thailand.
authors.forename: Julathep
authors.initials: J
authors.lastname: Kajornchaiyakul
authors.affiliation: Department of Operative Dentistry and Endodontics, Faculty of Dentistry, Mahidol University, Yothi Road, Rajthevee, Bangkok, Thailand.
authors.forename: Choltacha
authors.initials: C
authors.lastname: Harniratisai
keywords: Copper alloy; Cu-Al-Ni alloy; Dental alloy; Post and core