scholarly journals Microstructure and Mechanical Properties of NiTi-Based Eutectic Shape Memory Alloy Produced via Selective Laser Melting In-Situ Alloying by Nb

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2696
Author(s):  
Igor Polozov ◽  
Anatoly Popovich
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Selective Laser Melting ◽  
Mechanical Tests ◽  
Laser Melting ◽  
Heat Treated ◽  
Powder Particles ◽  
Martensitic Phase Transformations ◽  
Nb Addition

This paper presents the results of selective laser melting (SLM) process of a nitinol-based NiTiNb shape memory alloy. The eutectic alloy Ni45Ti45Nb10 with a shape memory effect was obtained by SLM in-situ alloying using a powder mixture of NiTi and Nb powder particles. Samples with a high relative density (>99%) were obtained using optimized process parameters. Microstructure, phase composition, tensile properties, as well as martensitic phase transformations temperatures of the produced alloy were investigated in as-fabricated and heat-treated conditions. The NiTiNb alloy fabricated using the SLM in-situ alloying featured the microstructure consisting of the NiTi matrix, fine NiTi+β-Nb eutectics, as well as residual unmelted Nb particles. The mechanical tests showed that the obtained alloy has a yield strength up to 436 MPa and the tensile strength up to 706 MPa. At the same time, in-situ alloying with Nb allowed increasing the hysteresis of martensitic transformation as compared to the alloy without Nb addition from 22 to 50 °C with an increase in Af temperature from −5 to 22 °C.

scholarly journals Phase Formation, Thermal Stability and Mechanical Properties of a Cu-Al-Ni-Mn Shape Memory Alloy Prepared by Selective Laser Melting

2015 ◽  
Vol 18 (suppl 2) ◽  
pp. 35-38 ◽  
Author(s):  
Piter Gargarella ◽  
Cláudio Shyinti Kiminami ◽  
Eric Marchezini Mazzer ◽  
Régis Daniel Cava ◽  
Leonardo Albuquerque Basilio ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Selective Laser Melting ◽  
Phase Formation ◽  
Laser Melting

Adjustment of the scan track spacing and linear input energy to fabricate dense, pseudoelastic Nitinol shape memory alloy parts by selective laser melting

2021 ◽  
pp. 1045389X2110639
Author(s):  
Mohammadreza Zamani ◽  
Mahmoud Kadkhodaei ◽  
Mohsen Badrossamay ◽  
Ehsan Foroozmehr
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Selective Laser Melting ◽  
Process Parameters ◽  
Room Temperature ◽  
Optimal Parameters ◽  
Research Groups ◽  
Laser Melting ◽  
Influence Of Process Parameters ◽  
Transformation Temperatures

Nitinol is a well-known shape memory alloy (SMA) which is widely used due to its unique properties such as shape memory effect and pseudoelasticity. However, challenges fabricating Nitinol parts have limited the use of this alloy. Nowadays, additive manufacturing methods, specifically selective laser melting (SLM), are being used as an alternative to conventional methods for fabricating Nitinol specimens. Achieving a dense structure and controlling the transformation temperatures in such products have been among the most important challenges for several research groups. In the present study, fabrication of dense Nitinol parts by SLM together with control of their transformation temperatures is investigated with the main purpose of achieving pseudoelastic products at room temperature. For this purpose, the effect of process parameters on density, transformation temperatures, microstructure, hardness, and shape memory response are studied. The influence of process parameters on transformation temperatures varies depending on the amount of power so that the effect of scan tracks spacing for high powers is more pronounced than that for low powers. The hardness and compressive strength of the parts are also affected by the process parameters. Accordingly, optimal parameters are found to fabricate dense pseudoelastic parts with the ability of strain recovery at ambient temperature.

scholarly journals Advances in Selective Laser Melting of Nitinol Shape Memory Alloy Part Production

Materials ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 809 ◽  
Author(s):  
Josiah Chekotu ◽  
Robert Groarke ◽  
Kevin O’Toole ◽  
Dermot Brabazon
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Selective Laser Melting ◽  
Processing Parameters ◽  
Inert Atmosphere ◽  
Influential Factors ◽  
Future Research ◽  
Laser Melting ◽  
High Quality ◽  
Thermal Cooling

Nitinol (nickel-titanium or Ni-Ti) is the most utilized shape memory alloy due to its good superelasticity, shape memory effect, low stiffness, damping, biocompatibility, and corrosion resistance. Various material characteristics, such as sensitivity to composition and production thermal gradients, make conventional methods ineffective for the manufacture of high quality complex Nitinol components. These issues can be resolved by modern additive manufacturing (AM) methods which can produce net or near-net shape parts with highly precise and complex Nitinol structures. Compared to Laser Engineered Net Shape (LENS), Selective Laser Melting (SLM) has the benefit of more easily creating a high quality local inert atmosphere which protects chemically-reactive Nitinol powders to a higher degree. In this paper, the most recent publications related to the SLM processing of Nitinol are reviewed to identify the various influential factors involved and process-related issues. It is reported how powder quality and material composition have a significant effect on the produced microstructures and phase transformations. The effect of heat treatments after SLM fabrication on the functional and mechanical properties are noted. Optimization of several operating parameters were found to be critical in fabricating Nitinol parts of high density. The importance of processing parameters and related thermal cooling gradient which are crucial for obtaining the correct phase structure for shape memory capabilities are also presented. The paper concludes by presenting the significant findings and areas of prospective future research in relation to the SLM processing of Nitinol.

The fabrication of NiTi shape memory alloy by selective laser melting: a review

2019 ◽  
Vol 25 (8) ◽  
pp. 1421-1432 ◽  
Author(s):  
Xizhang Chen ◽  
Kun Liu ◽  
Wei Guo ◽  
Namrata Gangil ◽  
Arshad Noor Siddiquee ◽  
...  
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Selective Laser Melting ◽  
Process Analysis ◽  
Research Direction ◽  
Process Equipment ◽  
Niti Shape Memory Alloy ◽  
Laser Melting ◽  
Content Type ◽  
Niti Sma

Purpose In recent years, the use of high performing materials, and application of additive manufacturing technology for industrial production has witnessed a steady rise and its expanse is only to increase in the future. “Selective laser melting (SLM) technique” for an exotic nickel-titanium (NiTi) shape memory alloy (SMA) is expected to a great facilitator to research in this area. The purpose of this paper is to put forth the research direction of NiTi shape memory alloy by selective laser melting. Design/methodology/approach This review also summaries and skims out the information on process equipment, adopted methodologies/strategies, effects of process parameters on important responses e.g. microstructure and comprehensive functional and mechanical properties of SLM-NiTi. In particular, the functional characteristics (i.e. shape memory effects and super-elasticity behavior), process analysis and application status are discussed. Findings Current progresses and challenges in fabricating NiTi-SMA of SLM technology are presented. Practical implications This review is a useful tool for professional and researchers with an interest in the field of SLM of NiTi-SMA. Originality/value This review provides a comprehensive review of the publications related to the SLM techniques of NiTi-SMA while highlighting current challenges and methods of solving them.

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