A study of B2↔B19↔B19′ two-stage martensitic transformation in a Ti50Ni40Cu10 alloy
Journal
Acta Metallurgica Et Materialia
Journal Volume
41
Journal Issue
3
Pages
747-759
Date Issued
1993
Author(s)
Abstract
The B2↔B19↔B19′ two-stage martensitic transformation in a Ti50Ni40Cu10 alloy has been investigated by electrical resistivity, DSC, X-ray diffraction and internal friction measurements. The shear modulus of B19 martensite has an unusually low value over a broad temperature range between the two shear modulus minima. The B2↔B19 transformation is thus proposed to proceed under the condition of deep shear modulus softening. X-ray diffraction results show that the B19↔B19′ is an incomplete transformation and that the monoclinic angle β of B19′ martensite will increasing with decreasing temperature. This indicates that the B19↔B19′ transformation has the characteristic of the continuously monoclinic distortion of B19′ martensite, which is similar to that of the continuously rhombohedral distortion of R-phase. The opposite behavior observed in electrical resistivity and DSC measurements for B2↔B19 and B19↔B19′ transformations is also discussed. © 1993.
Type
journal article