Internal friction of B2 → B19′ martensitic transformation of Ti50Ni50 shape memory alloy under isothermal conditions

✍ Scribed by S.H. Chang; S.K. Wu

• Publisher: Elsevier Science
• Year: 2007
• Tongue: English
• Weight: 536 KB
• Volume: 454-455
• Category: Article
• ISSN: 0921-5093
• DOI: 10.1016/j.msea.2006.11.157

✦ Synopsis

The inherent internal friction (IF PT + IF I ) B2→B19 of cold-rolled and annealed Ti 50 Ni 50 alloy that exhibits B2 → B19 martensitic transformation is studied under isothermal conditions. The tan δ value of (IF PT + IF I ) B2→B19 is proportional to σ 0 /ν 1/2 and its damping mechanism is thus related to stress-assisted martensitic transformation and stress-assisted motion of twin boundaries. The tan δ value of (IF PT + IF I ) B2→B19 is smaller than those of (IF PT + IF I ) B2→R and (IF PT + IF I ) R→B19 because the former shows no R-phase. The obliterated dislocations and defects after sufficient annealing can lower the tan δ value of the relaxation peak at about -60 • C.