**4. Conclusions**

In summary, a new SPD method, HSHPT, can successfully be used to manufacture bimetallic composites with an ultrafine grained structures. The achieved shape memory multilayer composites were composed of 2 to 32 layers of Ni50.3Ti and Ni49.6Ti alloys. The bonding of layers was achieved mainly by the high pressure imposed and short time high temperature reached during the high speed rotation of upper anvil. A very good joint was obtained, regardless of the number of layers or alternating them. The microstructure of composites was uniform where the bonding of adjacent layers could not be detected by optical microscopy and SEM. The SPD process was effective at refining both the alloys that made up the composite. As-HSHPT processed composite discs revealed martensitic transformation after deformation. The module diameter varied between 20 and 40mm, and was dependent on the number of layers and the degree of deformation applied. The thickness of the layers varied from 300 μm to 20 μm. HSHPT yields multilayered, fine structures and may, in future study, be adapted

for use for two-way SME. Future work will be also focus on the fabrication the new metallic UFG composites by HSHPT. This technology is capable of inducing thermocompression bonding starting from dissimilar materials. Multilayer composites with desirable mechanical, electrical, magnetic and biocompatibility properties provide the opportunity to create effective functional applications.

**Supplementary Materials:** The following are available online at http://www.mdpi.com/2075-4701/10/12/1629/s1.

**Author Contributions:** Conceptualization, C.G. and G.G.; methodology, C.G., G.G., F.M.B.F., P.A., V.S., M.M. and. B.M.G. investigation, C.G., P.A., M.M. and B.M.G. (OM, SEM), F.M.B.F. (DSC) and V.S. (TEM); writing—original draft preparation, C.G. and G.G.; writing—review and editing, V.S., G.G., C.G. and P.A. supervision, F.M.B.F. and V.S.; project administration, C.G. and G.G.; All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by 47PCCDI/2018 project and MANUNET 3 PN3-P3-302, gran<sup>t</sup> number 99-2019. F.M. Braz Fernandes acknowledges the funding of CENIMAT/I3N by National Funds through the FCT - Fundação para a Ciência e a Tecnologia, I.P., within the scope of the project refª UIDB/50025/2020-2023. Edgar Camacho (CENIMAT, FCT/UNL) is acknowledged for running the DSC tests.

**Conflicts of Interest:** The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.
