Martensitic transformation in constrained films

Journal Article · Tue Sep 01 04:00:00 EDT 1998 · Acta Materialia

DOI:https://doi.org/10.1016/S1359-6454(98)00165-7· OSTI ID:669802

Su, Q; Slutsker, J; Wuttig, M ^[1]

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1. Univ. of Maryland, College Park, MD (United States). Dept. of Materials Science and Engineering

A thermodynamic analysis is presented for the martensitic transformation in a constrained film upon cooling and heating. It is shown that this transformation proceeds with a variable self-strain corresponding to a variable polydomain structure of the martensite phase. Even the equilibrium microstructure develops irreversibly with changing temperature, i.e., the microstructure evolution paths for the direct and the reverse transformations are different. During the reverse transformation the stressed austenite, incompatible to martensite, is formed. The theory predicts a considerable shift of the temperature interval of transformation and its broadening due to the constraint. Experimental studies of the stress evolution with changing temperature in NiTi polycrystalline films on Si substrates support the principal thermodynamic conclusions.

• OSTI ID: 669802
• Journal Information: Acta Materialia, Journal Name: Acta Materialia Journal Issue: 14 Vol. 46; ISSN 1359-6454; ISSN ACMAFD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
AUSTENITE
CRYSTAL-PHASE TRANSFORMATIONS
MARTENSITE
NICKEL ALLOYS
STRESSES
TEMPERATURE DEPENDENCE
THERMODYNAMIC MODEL
THIN FILMS
TITANIUM ALLOYS