Effect of Nb Addition on Martensitic Transformation Behavior of AuTi-15Co Based Biomedical Shape Memory Alloys

• Shim Hyunbo

  Precision and Intelligence Laboratory, Tokyo Institute of Technology

• Tahara Masaki

  Precision and Intelligence Laboratory, Tokyo Institute of Technology

• Inamua Tomonari

  Precision and Intelligence Laboratory, Tokyo Institute of Technology

• Goto Kenji

  Tanaka Kikinzoku Kogyo K. K.

• Yamabe-Mitarai Yoko

  Functional Structure Materials Group, National Institute of Materials Science

• Hosoda Hideki

  Precision and Intelligence Laboratory, Tokyo Institute of Technology

Abstract

The effect of quaternary addition of Nb being from 0 to 2 mol% on the phase constitution, phase transformation behavior and shape memory behavior of Au-50 mol%Ti-15 mol%Co (AuTiCo) alloys is studied. X-ray diffraction analysis shows that, with increasing Nb concentration, the primary phase appeared at room temperature changes from B19 orthorhombic martensite phase to B2 cubic parent phase, and that all the lattice parameters are not largely changed by Nb addition. The maximum transformation strain evaluated in 2 mol%Nb-added AuTiCo is 7.4%. Differential scanning calorimetry revealed that the reverse martensitic transformation finish temperature (A_f) decreases from 414 K in Nb-free AuTiCo to 303 K by 2 mol%Nb addition. The ratio of A_f change by Nb addition is evaluated to be −55 K/mol%Nb, that is comparably larger than −31 K/mol%Nb in NiTi. These results indicate that Nb addition is effective to stabilize B2 parent phase. AuTiCo alloy containing less than 2 mol%Nb exhibits shape memory effect with 90% shape recovery ratio. Besides, AuTiCo containing 2 mol%Nb exhibits 2.8% superelastic shape recovery at room temperature as well as 7.4% maximum transformation strain. Therefore, Nb addition to AuTiCo is effective to decrease the martensitic transformation temperature and to improve superelasticity, although the transformation temperature hysteresis increases by Nb addition, similar to Nb-added NiTi.

Journal

• MATERIALS TRANSACTIONS

  MATERIALS TRANSACTIONS 56 (3), 429-434, 2015

  The Japan Institute of Metals and Materials

Keywords

• AuTiCo
• niobium addition
• martensitic transformation behavior
• biomedical shape memory alloys
• shape memory effect
• superelasticity

Details

• CRID: 1390282679230342400
• NII Article ID: 130004825275
• NII Book ID: AA1151294X
• DOI: 10.2320/matertrans.m2014418
• ISSN: 13475320
• ISSN: 13459678
• NDL BIB ID: 026220739
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I026220739
• Web Site: https://www.jstage.jst.go.jp/article/matertrans/56/3/56_M2014418/_pdf
• Text Lang: en
• Data Source:
  • JaLC
  • NDL
  • Crossref
  • CiNii Articles
  • KAKEN
• Abstract License Flag: Disallowed