Workshop on Shape Memory Alloys Processing ...

Workshop on Shape Memory Alloys Processing, Properties and Applications FCT/UNL, 11/10/2017

Severe plastic deformation

Laser welding

In situ study of thin film growth (sputter)

Endodntic files / chanical process

Fatigue fracture

Orthodontic archwire

Strain monitoring

In situ study of thermome-

MIDAS Micro and Nanoscale Design of Thermally Actuating Systems

Autor(es) F.M. Braz Fernandes F.M. Braz Fernandes Xingke Zhao Rodolfo Teixeira, A.S. Paula

Instituição CENIMAT CENIMAT University of Science and Technology, Beijing

PROGRAMA Apresentação Abertura. Apresentação do projecto MIDAS SMAs at CENIMAT

Hora 09h10 - 09h20 09h20 – 09h40

Powder metallurgy of NiTi based alloys

09h40 - 10h00

NiTi sheets, wires and powder metallurgy pro10h00 - 10h20 duction at IME. Russian Study of the new shape memory alloys and Viktor Koledov Academy of their applications in micromechanics, alterna- 10h20 - 10h40 Sciences tive energy and dentistry. Coffee Break / Posters 10h40 - 11h00 Filipe Neves, José Brito Research work at LNEG in the field of shape LNEG 11h00 - 11h20 Correia memory alloys Patrícia Rodrigues, CENIMAT In situ studies of thermomechanical processing F.M. Braz Fernandes, 11h20 - 11h40 IME of NiTi A.S. Paula J.P. Oliveira, Rosa CENIMAT Miranda, F.M. Braz UNIDEMI NiTi laser welding 11h40 - 12h00 Fernandes WU Pedro Carreira, CEMMPRE Additive manufacturing of Ni/Ti alloys 12h00 - 12h20 Teresa Vieira Almoço Livre 12h30 - 14h00 F.M. Braz Fernandes, CENIMAT Functionally graded wires 14h00 - 14h20 Edgar Camacho UNIDEMI Patrick Inácio, Telmo Prototype for production and evaluation of UNIDEMI 14h20 - 14h40 Santos functionally graded Ni-Ti wires Ni/Ti reactive multilayers for joining NiTi shape André Cavaleiro INEGI 14h40 - 15h00 memory alloys to Ti aloys Coffee Break / Posters 15h00 - 16h00 F.M. Braz Fernandes CENIMAT Conclusões. Encerramento. 16h00 - 16h15 IME

Posters Filipe Santos Edgar Camacho Telmo Gomes dos Santos P. Inácio F.M. Braz Fernandes Edgar Camacho F.M. Braz Fernandes Patrícia Rodrigues Rafaella Magalhães F. M. Braz Fernandes André Cavaleiro Rui M.S. Martins Zhao

DEC

Exploratory research with Shape-memory alloys in Civil Engineering

CENIMAT UNIDEMI

Production and characterization of functionally P2 graded wires from NiTi shape memory alloys

CENIMAT

Aplicação de ligas com memória de forma a processos de união

P3

CENIMAT

In situ studies of NiTi and NiTiCu orthodontic wires

P5

INEGI IST USTB

???? ????? ???? Bottom-up Nanoassembling and NanomanuRussian Academy of facturing using mechanical Nanomanipulation Svetlana von Gratowski, Victor Sciences, Moscow, based on Shape Memory Effect. Prospects Koledov Russia and problems of the future applications of MIDAS results in advanced nanotechnology. Critical Analyses on the Instrumented UltramiRodolfo Teixeira IME crohardness Results on Aging NiTi Alloy in Distinct Phase Fields A.R. Alves, F.M. Braz Fernandes CENIMAT Heat treatment of endodontic files ORAL PRESENTATIONS

P1

P6 P7 P8 P9

P10 P11

SMA at CENIMAT F.M. Braz Fernandes, Rui M.S. Martins, K.K. Mahesh, R.J.C. Silva, A.S. Paula, F. Neves, J. Brito Correia, S.V. Correia, R. Magalhães, P. Fernandes, E. Camacho, P. Inácio, T. Santos A general overview of 15 years of Activity on shape memory alloys is presented, covering: - In situ studies of the growth of NiTi thin films, - Thermomechanical processing, - Severe plastic deformation, - Applications in dentistery (orthodontics and endodontics), - Powder metallurgy, - Functionally graded SMA Powder metallurgy of NiTi based alloys X. Zhao The presentation mainly contains: 1)Introduction to powder metallurgy;2)Conventional processes;3)Additive manufacturing. NiTi sheets, wires and powder metallurgy production at IME Rodolfo da Silva Teixeira, Andersan S. Paula This presentation consists of contextualizing the work on NiTi alloys that were done at UFF (Universidade Federal Fluminense) and IME (Instituto Militar de Engenharia) before and during the Midas project. This work covers the production of hot and cold rolled sheets of equiatomic NiTi, NiTiFe, NiTiCu, NiTiAl and NiTi alloys with very high Ni content (between 58 and 60%) processed by VAR and VIM. Also equiatomic NiTi alloys has been studied by powder metallurgy starting from mixtures of Ti and Ni powders obtained, respectively, from the hydration–dehydration method and from a process consisting in the recovery of nickel from nickel scrap. Study of the new shape memory alloys and their applications in micromechanics, alternative energy and dentistry. Results of MIDAS activity in Kotelnikov IRE RAS, Moscow in 2014-2017. Victor Koledov, Svetlana von Gratowski The report is devoted to the following results of MIDAS: Presentation of Kotelnikov IRE RAS, Moscow. Study of layered composites with shape memory effect under temperature and magnetic field control. Applications of FIB technology for shape memory microactuators and nanotweezers design. First experiments on nanomanipulation by SME composite nanotweezers. Nanostructural TiNi alloy with SME and its application for dental implants design and treatment of severe cases of parodontosis and adentia. Elastocaloric and Magnetocaloric effects in SME alloys and prospects of their applications in alternative energy. Research work at LNEG in the field of shape memory alloys Filipe Neves, José Brito Correia The research work at LNEG in the field of shape memory alloys (SMAs) has been mainly dedicated to the processing of Ni-Ti based alloys by powder metallurgy. Two innovative powder metallurgical processing routes were developed: MARES – Mechanically Activated Reactive Extrusion Synthesis and MARFOS – Mechanically Activated Reactive Forging Synthesis. These two processing routes comprise mechanical activation of elemental powder mixtures and densification through extrusion or forging. Within the framework of MIDAS project (PIRSES-GA-2013-612585; FP7-PEOPLE-2013-IRSES) LNEG is involved in WP1-Structural optimization by Mechanical Alloying (partner leader of the WP), WP3-Micro and nanoscale characterization and in WP5-Applicative design. Main activities have been dedicated to the selection of the adequate mechanical alloying processing parameters and to composition optimization with the objective of improving the process yield and minimize oxidation issues. This is being performed in a straight collaboration with all the MIDAS partners participating in the above mentioned WPs. A very promising field of the SMAs application, where LNEG has particular interest, is the development of novel solid-state refrigeration techniques based on the caloric effect from solid-state transformation driven by external stimuli. This has the potential to be an environmentally friendly alternative to the conventional vapor compression based cooling process. Ni-Ti based alloys, especially, show large elastocaloric effects and exhibit large latent heats which is a necessary material property for the development of an efficient solid-state based cooling process. In situ studies of thermomechanical processing of NiT

Patrícia Rodrigues, F.M. Braz Fernandes, A.S. Paula The thermomechanical processing of SMA is very important in this type of alloy because it can improve their characteristics, providing good functional and mechanical characteristic for their final application. The application for orthodontics requires the final temperature (Af) to be close to room temperature. To verify this condition DSC test was applied. In order to evaluate the hot-workability and processing parameters from the as-cast sample to aging step, in situ deformation experiments were conducted with the high energy X-ray diffraction (HEXRD) setup of the HZG beamline HEMS (P07-EH3) at Petra III, DESY, Hamburg. This study aims to simulate the process of the NiTi alloy in order to identify possible optimization of the thermomechanical processing of NiTi alloy. Laser joining of NiTi to Ti6Al4V using a Niobium interlayer J.P. Oliveira, Rosa M. Miranda, F. M. Braz Fernandes, N. Zhou Joining NiTi to Ti6Al4V is of great interest for applications in the biomedical and aerospace fields. Despite the importance, no joining techniques have been developed that avoid the formation of brittle intermetallics to produce high strength joints. In this work, Nb was used as an interlayer to prevent the formation of these brittle phases when joining NiTi to Ti6Al4V. The presence of this interlayer ensured that crack free welds were obtained and no brittle intermetallic compounds were observed. The Nb interlayer was of a much higher melting temperature than the base materials so the bulk Nb did not melt during the joining process, acting as a diffusion barrier between the NiTi and Ti6Al4V. The laser was focused on the Ti6Al4V side of the joint, which joined the Ti6Al4V and Nb by fusion welding. At this interface a (Ti, Nb) region was formed due to dilution of the Nb and mixing with the Ti6Al4V. At the NiTi–Nb interface a eutectic reaction was responsible for joining. Mechanical testing of the joints revealed that the minimum tensile strength matched the ultimate tensile strength of the weakest material, Nb. These results highlight new possibilities for the use of high melting point filler materials when joining NiTi to dissimilar materials, so that the formation of undesired phases can be avoided. Additive manufacturing of Ni/Ti alloys Daniel Gatões, Pedro Carreira, M. Teresa Vieira Nickel-Titanium (NiTi) is the most applied Shape Memory Alloy (SMA), due their unusual properties. SMA is being more and more applied to plastic moulding industry. However, it is hard to produce new shapes using conventional subtractive manufacturing, due to high ductility and poor machining of NiTi. The main products available in the market are in “standard” configurations like rods, wires, bars, tubes, sheets and strips. Additive manufacturing (AM) seems to be a logical alternative to conventional techniques, going from powders to complex-shaped parts through an initial CAD data. Therefore, AM allows the usage of functional NiTi in different industries, e.g. mechanical, medical and aerospace. A review of SLM technique focuses on initial powders and their producing methods, processing parameters, interfaces, and their consequences in final microstructure, defects, and transformation temperatures, and consequently in functional and mechanical properties. Moreover, the future of this processing technology regarding NiTi, is also approaching. Different challenges must be overcome to attain NiTi parts/devices by SLM with the desired properties. Functionally graded wires from NiTi shape memory alloys F. M. Braz Fernandes, E. Camacho, P. Rodrigues, P. Inácio, T. G. Santos The present work aims for the production of controlled functionally graded NiTi through localized heat treatments, taking advantage of its high sensitivity to precipitation. Through heat treatment by Joule effect (JE), it is possible to create a localized heat treatment (HT) on small segments of NiTi Ni-rich wires. DSC, thermomechanical and in-situ XRD during mechanical tests were performed. With this localized heat treatment it was possible to establish a gradient of matrix compositional changes along the wire, producing differentiated thermo-mechanical behavior of the wire. Also, the reproducibility of the same heat treatment performed on various wires has been checked with DSC tests. Prototype for production and evaluation of functionally graded Ni-Ti wires P. L. Inácio, E. Camacho, P.F. Rodrigues, R. M. Miranda, A. Velhinho, F. M. Braz Fernandes, T. G. Santos A functional prototype was created to produce differentiated heat treatments of Ni-Ti wires using Joule effect as heat input source. The prototype developed allows the movement of electrodes, during the treatment, producing a dynamic profile of electrical current and time instead of conventional heat treatment with constant parameters. Additionally, a system was added to apply and measure load in the wire. Nondestructive techniques were used to monitor the heat-treatment in real time to detect changes in electrical resistivity and phase changes after the treatment by a non-contact technique. Numerical simulation was performed to design an eddy-current probe for non-contact evaluation.

POSTERS Exploratory research with Shape-memory alloys in Civil Engineering ADAPTIVE STRUCTURES: SHAPE-MORPHING FOR FREQUENCY TUNNING LOCK-IN EFFECT Filipe Amarante dos Santos The present work explores the capabilities of a tensegrity-inspired tower with regard to frequency tuning by shape morphing. To change the configuration of the proposed structure, shape-memory-alloy actuators are used. This actuation principle also takes advantage of the variation of the elastic modulus of shape-memory alloys associated with the martensitic transformation. The temperature modulation of the shape-memoryalloy wires is successfully achieved by Joule heating, through a proportional-integral-derivative controller, to change between a low-temperature shape and a high-temperature shape. The implementation of a shorttime-Fourier-transform control algorithm allows for the correct identification of the dominant input frequency, associated with the dynamic excitation. This information is used to automatically change the configuration of the structure in order to shift its natural frequency away from that of the dynamic excitation. With this frequency tuning, one obtains a reduction of the accelerations throughout the structure up to about 80%. The good performance of the proposed control approach gives promising indications regarding the use of tensegrity systems, in combination with shape-memory alloys, for shape-morphing applications, and, in particular, for self-tuning structures. Production and characterization of functionally graded wires from NiTi shape memory alloys E. Camacho, P. Rodrigues, F. M. Braz Fernandes, P. Inácio, T. G. Santos The present work aims for the production of controlled functionally graded NiTi through localized heat treatments, taking advantage of its high sensitivity to precipitation. Through heat treatment by Joule effect(JE), it is possible to create a localized heat treatment (HT) on small segments of NiTi Ni-rich wires. DSC, thermomechanical and in-situ XRD during mechanical tests were performed. With this localized heat treatment it was possible to establish a gradient of matrix compositional changes along the wire, producing differentiated thermo-mechanical behavior of the wire. Also, the reproducibility of the same heat treatment performed on various wires has been checked with DSC tests. Shape memory rivets E. Camacho, F.M. Braz Fernandes In this study, various samples of a shape memory alloy (SMA) NiTi Ti-rich rod were cut and used to join two components trough shape memory effect (SME). There is no indication of an extensive use of such materials for this purpose. A recent patent (2013) in the field of aeronautics opens interesting perspectives for this kind of joining processes. In the concept study and viability of a rivet with SME, DSC, dilatometric and insitu XRD thermomechanical tests were performed. These tests and respective characterization demonstrated the feasibility of using rivets with SME. Also, the actuation force by SME, promoted a localized hardening of the joined material, hence improving the contact interface between rivets and component. In situ studies of NiTi and NiTiCu orthodontic wires Patrícia Rodrigues, Francisco Manuel Braz Fernandes, Edgar Camacho, Rafaela Magalhães In this study, a class of NiTiCu orthodontic wires thermal activitied was analyzed. This wire (CuNiTi Thermocopper NiTi – 35ºC/Morelli) has 6%Cu. Microstructural characterization of the wire was performed using Differential Scanning Calorimetry (DSC), in situ synchrotron-based x-ray diffraction (SXRD) and three-point flexion test was performed by TMA analysis in the temperature range (05 to 40 °C). This study provided a better understanding of the behavior of these wires. Ni-Ti surface with depressed Ni concentration prepared by plasma immersion ion implantation: superelasticity at body temperature Rui M.S. Martins, N. Barradas, E. Alves, D. Henke, H. Reuther, N. Schell, M.J. Carmezim, T.M. Silva, J.C.S. Fernandes. The plasma-immersion ion implantation (PIII) technique was used to modify and improve the surface of a Ni-Ti alloy (~ 50.4 at.% Ni) for biomedical applications. PIII technique allows the formation of a diffuse interface between the bulk material and the modified layers, reducing the tendency for delamination. Techniques like thermal oxidation and nitriding also lead to an improved corrosion resistance and Ni-depleted Ni-Ti surface but require high processing temperatures leading to modification of the phase transformation characteristics and loss of specific mechanical properties. Oxygen and nitrogen PIII experiments were performed with a working pressure of 0.2 Pa, in a chamber equipped with an RF plasma source operating at a power of 350 W. High voltage pulses of either 20 or 40 kV were applied to the samples using a frequency of 400 Hz. The sample holder was not intentionally heated (T < 125°C).

The depth profiles of the elemental distribution in the alloy surface region, obtained by Auger electron spectroscopy (AES), show the formation of a Ti-rich oxide layer for the experiments carried out with oxygen. In the case of the experiments performed with nitrogen, the formation of titanium oxynitride (TiNxOy) is observed. Moreover, AES data show an almost Ni-free fraction for experiments performed with 40 keV. The high value of film resistance (electrochemical impedance spectroscopy analysis) suggests a very good corrosion resistance, which can be associated with the low Ni concentration at the surface of film. Synchrotron radiation-based X-ray diffraction data acquired in transmission mode show that the PIII technique only changes the structure of the Ni-Ti alloy top layer preserving superelastic behaviour at body temperature. Rapid preparation and characterization of NiTi alloy obtained by ball-milling NiTi2-Ni combination of powders X. K. Zhao, Kuan Liu, F. Neves, F. M. Braz Fernades, J. H. Huang, D. Y. Liu The high demand for NiTi powders requires developing new processing methods. A rapid approach for preparation of NiTi alloy by mechanical alloying using NiTi2-Ni starting powders has been studied. The results show that mechanical alloying process is much faster with NiTi2-Ni powders than with conventional Ni-Ti powders. Ultra-fine NiTi particles with a homogenous composition can be obtained by ball-milling NiTi2-Ni at 400 rpm for 120 min. Rapid preparation and ultra-fine particles of NiTi alloy are mainly attributed to the fragmentation of NiTi2 which enhances the mechanical alloying mechanism of fracturing and coldwelding in the very early stage of milling process.\ Bottom-up Nanoassembling and Nanomanufacturing using mechanical Nanomanipulation based on Shape Memory Effect. Prospects and problems of the future applications of MIDAS results in advanced nanotechnology. Dr Svetlana von Gratowski, Dr Victor Koledov The report is devoted to discussion of the future applications of the nano-tweezers, developed during MIDAS-project and problems on this way. The smallest and the fastest in the World nano-tweezers are able to manipulate real nano-objects like nanotubes, nanowires, etc. SME based nano-manipulation can be used for nano manufacturing and nanointegration for nanoelectronics, nanoenergy and lab-on-ship medical diagnostics . The ongoing research Projects in these directions with BRICS countries are presented. The problems on these way are discussed including control of the dispersive forces (Wan-der-Waals and Kazimir) of the interaction of the nanotweezers and the nanoobjects to be manipulate. Heat treatment of endodontic files F. M. Braz Fernandes, Ana Rita Alves, A. Machado, J. P. Oliveira Three brands of rotary nickel-titanium endodontic instruments with some comparable geometric features but with different cross-section (similar tip size and same taper of .04) were selected for this study: MTwo .04(35) (VDW GmbH, Germany), K3 .04(30) (SybronEndo, Mexico) and K3XF .04(30) (SybronEndo, Mexico). K3XF is made from novel R-phase heat-treated metal alloy while all other files were made from traditional Ni-Ti alloy. The instruments were analyzed under the following conditions: i) as-received (AR), ii) heat treated at 350ºC, iii) heat treated at 400ºC. The transformation temperatures were determined by differential scanning calorimeter (DSC). Compared to conventionally K3 and Mtwo files, R-phase heat treatment K3XF file showed higher transformation temperatures. These results also showed that heat treatments increase the transformation temperatures. Mechanisms of martensite formation in laser welding of NiTi SMA J.P. Oliveira, Rosa M. Miranda, F. M. Braz Fernandes Extensive work has been reported on the microstructure of laser-welded NiTi alloys either superelastic or with shape memory effect, motivated by the fact that the microstructure affects the functional properties. However, some effects of laser beam/material interaction with these alloys have not yet been discussed. This paper aims to discuss the mechanisms for the occurrence of martensite in the heat-affected zone and in the fusion zone at room temperature, while the base material is fully austenitic. For this purpose, synchrotron radiation was used together with a simple thermal analytic mathematical model. Two distinct mechanisms are proposed for the presence of martensite in different zones of a weld, which affects the mechanical and functional behavior of a welded component.