2025/03/18 by Dobromyslov, Arkadiy V., Taluts, Nina I.
#FOS: Physical sciences #Physical sciences
paper · doi:10.48612/letters/2025-1-15-21
The curve of the beginning of the martensitic transformation Ms is a fundamental characteristic that determines the start of the phase transformation without diffusion by an ordered cooperative rearrangement of the crystal lattice. For zirconium alloys, the position of the Ms curves are practically unknown. Using X-ray diffraction analysis, optical metallography, and transmission microscopy, a systematic study of the conditions for the retaining of the metastable β-phase in binary zirconium alloys with d-metals of groups 5 –10 of the periods 5 and 6 has been carried out. It is found that the boundary, separating the alloys in which the martensitic β → α'(α'') transformation occurs and the alloys in which it is absent, depends on the position of the d-metal in the Periodic Table. It is shown that the variation of the β-phase lattice parameter with composition obeys Vegard’s law and all experimentally obtained straight lines for alloys of different systems intersect on the ordinate axis at one point. The coordinate of this point, equal to аβ = 0.3587 nm, corresponds to the lattice parameter of the β-phase of pure zirconium under room temperature. Based on the data obtained, the relative positions of the start temperatures of martensitic β → α'(α'') transformation have been determined. It has been found that the relative position of the Ms curves for zirconium alloys is similar to the relative position of the Ms curves for titanium alloys and is determined by the size factor.