Structural changes of TiPt high-temperature shape memory alloys induced by high pressure torsion

The microstructure of a TiPt high temperature shape memory alloy induced by high pressure torsion (HPT) was studied using synchrotron radiation experiments and transmission electron microscopy. Upon the severe plastic deformation, the parent B19 martensite is strongly refined and highly strained. While neither strong chemical disorder nor amorphization are encountered, the occurrence of crystal reflections is observed that can be indexed in terms of the L1(0) phase and long range ordered stacking structures. The occurrence of the L1(0) phase might be triggered by the high hydrostatic stress as well as shear stress superimposed during the HPT. The austenite and martensite start and finish temperatures of TiPt are not affected by the HPT since upon heating, recrystallization occurs prior to the onset of the reverse martensite to austenite transformation. (C) 2022 Elsevier B.V. All rights reserved.

Automated summary

The microstructure of a TiPt high temperature shape memory alloy is studied under high pressure torsion (HPT) using synchrotron radiation experiments and transmission electron microscopy. Severe plastic deformation leads to refinement and strain of the B19 martensite, while no chemical disorder or amorphization is observed. Crystal reflections indexed as the L1(0) phase and long range ordered stacking structures are observed, which may be triggered by the high hydrostatic and shear stresses during HPT. The HPT does not affect the start and finish temperatures of the austenite and martensite transformations in TiPt, as recrystallization occurs prior to the reverse martensite to austenite transformation.