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.

Influence of processing parameters on the fabrication of a Cu-Al-Ni-Mn shape-memory alloy by selective laser melting

2016 ◽  
Vol 11 ◽  
pp. 23-31 ◽  
Author(s):  
T. Gustmann ◽  
A. Neves ◽  
U. Kühn ◽  
P. Gargarella ◽  
C.S. Kiminami ◽  
...  
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Selective Laser Melting ◽  
Processing Parameters ◽  
Laser Melting

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

Parameter optimization of aluminum alloy thin structures obtained by Selective Laser Melting

MRS Advances ◽  
2019 ◽  
Vol 4 (55-56) ◽  
pp. 2997-3005
Author(s):  
Malena Ley Bun Leal ◽  
Barbara Bermudez-Reyes ◽  
Patricia del Carmen Zambrano Robledo ◽  
Omar Lopez-Botello
Keyword(s):  
Selective Laser Melting ◽  
Process Parameters ◽  
Orthogonal Design ◽  
Processing Parameters ◽  
Future Research ◽  
Laser Melting ◽  
Complex Process ◽  
The Relationship ◽  
Fabrication Parameters

ABSTRACTSelective Laser Melting (SLM) involves numerous fabrication parameters, the interaction between those parameters determine the final characteristics of the resulting part and because of the latter, it is considered a complex process. Low-density components is one of the main issues of the SLM process, due to the incorrect selection of process parameters. These defects are undesired in high specialized applications (i.e. aerospace, aeronautic and medical industries). Therefore, the characterization of the defects (pores) found in aluminum parts manufacture by SLM and the relationship with fabrication parameters was performed. A robust orthogonal design of experiments was implemented to determine process parameters, and then parts were manufactured in SLM. Relative density of the samples was then characterized using the Archimedes principle and microscopy; the data was then statistically analyzed in order to determine the optimal process parameters. The main purpose of the present research was to establish the best processing parameters of an in-house SLM system, as well as to characterize the pore geometry in order to fully eliminate pores in a future research.

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 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.

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