Internal friction of R-phase and B19′ martensite in equiatomic TiNi shape memory alloy under isothermal conditions

• Published in: Journal of alloys and compounds 2007-06, Vol.437 (1), p.120-126
• Main Authors: Chang, S.H., Wu, S.K.
• Format: Article
• Language: English
• Subjects: Anelasticity, internal friction, stress relaxation, and mechanical resonances; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Internal friction; Martensite; Martensitic transformations; Materials science; Mechanical and acoustical properties of condensed matter; Phase diagrams and microstructures developed by solidification and solid-solid phase transformations; Physics; Shape memory alloy; Thermal (dynamic mechanical) analysis
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2006.07.092

The intrinsic internal friction IF I of R-phase and B19′ martensite are composed of static internal friction IF S and dynamic internal friction IF D. The tan δ values of I F S R and I F S B 1 9 ′ are both proportional to σ 0/ υ 1/2 and are related to the stress-assisted motions of twin boundaries. The tan δ values of I F S R are higher than those of I F S B 1 9 ′ is owing to the softer storage modulus E 0 in R-phase. The tan δ values of I F D B 1 9 ′ are linearly proportional to T ˙ / υ 1 / 2 . The occurrence of relaxation peak at ≈−60 °C is found to come from the I F S B 1 9 ′ , instead of the I F D B 1 9 ′ .