Two-step transient liquid phase bonding of NiTi to Ti-6Al-4V through a NbZrW barrier
Abstract
Dissimilar joining of NiTi to Ti-6Al-4V (Ti-64) is limited by brittle Ti2Ni formation and degradation of NiTi functionality. A two-step transient liquid phase (TLP) route was developed in which a refractory NbZrW diffusion barrier converts the incompatible couple into two independently bondable interfaces. The barrier plays a different role for each alloy: a reactive substrate for NiTi, dissolving to form a Ti-rich Ni-Ti-Nb liquid that infiltrates its own grain boundaries and is terminated by selective Ti absorption into the barrier; and an inert substrate for Ti-64, joined through contact melting of a sacrificial Cu foil. Both interfaces are fully dense and free of continuous intermetallic layers. In tension, joints spanning both interfaces began transforming at 350 MPa, exhibited a stress plateau to 2.5 global strain (consistent with stress-induced transformation of the NiTi half of the gauge) and failed beyond the plateau at 380-410 MPa. Five load-unload cycles to 460 MPa showed stable superelastic loops with minor ratcheting. These results demonstrate that a diffusion barrier enables dissimilar TLP joining of otherwise incompatible alloys.
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BibTeX
@misc{cao2026twostep,
title = {{Two-step transient liquid phase bonding of NiTi to Ti-6Al-4V through a NbZrW barrier}},
author = {Zhaoxi Cao and Samuel Price and John P. Reidy and Ian McCue},
howpublished = {arXiv},
year = {2026},
month = aug,
doi = {10.48550/arxiv.2608.30117},
eprint = {2608.30117},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2608.30117},
note = {CC BY-NC-ND 4.0},
}
RIS
TY - UNPB
TI - Two-step transient liquid phase bonding of NiTi to Ti-6Al-4V through a NbZrW barrier
AU - Zhaoxi Cao
AU - Samuel Price
AU - John P. Reidy
AU - Ian McCue
PY - 2026
DA - 2026/08/31
PB - arXiv
DO - 10.48550/arxiv.2608.30117
UR - https://arxiv.org/abs/2608.30117
AB - Dissimilar joining of NiTi to Ti-6Al-4V (Ti-64) is limited by brittle Ti2Ni formation and degradation of NiTi functionality. A two-step transient liquid phase (TLP) route was developed in which a refractory NbZrW diffusion barrier converts the incompatible couple into two independently bondable interfaces. The barrier plays a different role for each alloy: a reactive substrate for NiTi, dissolving to form a Ti-rich Ni-Ti-Nb liquid that infiltrates its own grain boundaries and is terminated by selective Ti absorption into the barrier; and an inert substrate for Ti-64, joined through contact melting of a sacrificial Cu foil. Both interfaces are fully dense and free of continuous intermetallic layers. In tension, joints spanning both interfaces began transforming at 350 MPa, exhibited a stress plateau to 2.5 global strain (consistent with stress-induced transformation of the NiTi half of the gauge) and failed beyond the plateau at 380-410 MPa. Five load-unload cycles to 460 MPa showed stable superelastic loops with minor ratcheting. These results demonstrate that a diffusion barrier enables dissimilar TLP joining of otherwise incompatible alloys.
ER -