Ageing effects on ordering degree and morphology of 18R-type martensite in shape memory CuZnAl alloys

Journal Article · Thu May 01 04:00:00 EDT 1997 · Materials Research Bulletin

DOI:https://doi.org/10.1016/S0025-5408(97)00024-X· OSTI ID:509195

Kayali, N; Oezgen, S; Adiguezel, O ^[1]

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1. Firat Univ., Elazig (Turkey)

Ageing effects in CuZnAl alloys have been investigated by X-ray diffraction and optical microscopy. The splittings observed in some selected diffraction peaks due to the monoclinicity of the martensite unit cell by basal plane distortion are referred to as monoclinic distortion. The spacing difference, {Delta}d, between some selected pairs of peaks may be used as a parameter to reflect the ordering degree in CuZnAl alloys, and the extent of {Delta}d difference and monoclinic distortion may depend on the type and degree of long range order or alloy composition. The variation of {Delta}d parameters for both as-quenched and post-quench {beta}-phase annealed specimens show a trend to decrease with holding duration at room temperature. This trend is closely related to the martensite stabilization, and this process is mainly due to the rearrangement of atoms in martensite lattice. Self-accommodating martensite morphology which has a diamond-like configuration has been observed in both as-quenched and post-quench heat-treated specimens. Parallel bands defined as lamellar martensite or twin-like morphologies have also been formed on the martensite plates, and interlamellar boundaries are not as straight as twin boundaries.

• OSTI ID: 509195
• Journal Information: Materials Research Bulletin, Journal Name: Materials Research Bulletin Journal Issue: 5 Vol. 32; ISSN MRBUAC; ISSN 0025-5408
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
AGING
ALUMINIUM ALLOYS
COPPER ALLOYS
CRYSTAL STRUCTURE
CRYSTAL-PHASE TRANSFORMATIONS
MARTENSITE
MONOCLINIC LATTICES
MORPHOLOGY
SHAPE MEMORY EFFECT
ZINC ALLOYS