scholarly journals In Search of the Optimal Conditions to Process Shape Memory Alloys (NiTi) Using Fused Filament Fabrication (FFF)

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4718
Author(s):  
Pedro Carreira ◽  
Fábio Cerejo ◽  
Nuno Alves ◽  
Maria Teresa Vieira
Keyword(s):  
Additive Manufacturing ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Sintering Temperature ◽  
Production Costs ◽  
Layer By Layer ◽  
Secondary Phases ◽  
Fused Filament Fabrication ◽  
Near Net Shape ◽  
Niti Shape Memory Alloys

This research was performed so as to investigate the additive manufacturing of NiTi shape memory alloys, which is associated with direct processes, such as selective laser melting. In addition to its expensive production costs, NiTi readily undergoes chemical and phase modifications, mainly as a result of Ni loss during processing as a result of high temperatures. This research explores the potential usefulness of NiTi as well as its limitations using indirect additive processes, such as fused filament fabrication (FFF). The first step was to evaluate the NiTi critical powder volume content (CPVC) needed to process high-quality filaments (via extrusion). A typical 3D printer can build a selected part/system/device layer-by-layer from the filaments, followed by debinding and sintering (SDS), in order to generate a near-net-shape object. The mixing, extruding (filament), printing (shaping), debinding, and sintering steps were extensively studied in order to optimize their parameters. Moreover, for the sintering step, two main targets should be met, namely: the reduction of contamination during the process in order to avoid the formation of secondary phases, and the decrease in sintering temperature, which also contributes to reducing the production costs. This study aims to demonstrate the possibility of using FFF as an additive manufacturing technology for processing NiTi.

The electron beam freeform fabrication of NiTi shape memory alloys. Part I: Microstructure and physical–chemical behavior

2020 ◽  
pp. 146442072097505
Author(s):  
RPM Guimarães ◽  
F Pixner ◽  
G Trimmel ◽  
J Hobisch ◽  
T Rath ◽  
...  
Keyword(s):  
Electron Beam ◽  
Additive Manufacturing ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Nickel Titanium ◽  
Freeform Fabrication ◽  
Austenitic Transformation ◽  
Columnar Grains ◽  
One Step ◽  
Niti Shape Memory Alloys

Nickel–titanium alloys are the most widely used shape memory alloys due to their outstanding shape memory effect and superelasticity. Additive manufacturing has recently emerged in the fabrication of shape memory alloy but despite substantial advances in powder-based techniques, less attention has been focused on wire-based additive manufacturing. This work reports on the preliminary results for the process-related microstructural and phase transformation changes of Ni-rich nickel–titanium alloy additively manufactured by wire-based electron beam freeform fabrication. To study the feasibility of the process, a simple 10-layer stack structure was successfully built and characterized, exhibiting columnar grains and achieving one-step reversible martensitic–austenitic transformation, thus showing the potential of this additive manufacturing technique for processing shape memory alloys.

scholarly journals Additive manufacturing of NiTi shape memory alloys using pre-mixed powders

2019 ◽  
Vol 271 ◽  
pp. 152-161 ◽  
Author(s):  
C. Wang ◽  
X.P. Tan ◽  
Z. Du ◽  
S. Chandra ◽  
Z. Sun ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Niti Shape Memory Alloys

scholarly journals A Short Review on the Microstructure, Transformation Behavior and Functional Properties of NiTi Shape Memory Alloys Fabricated by Selective Laser Melting

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1683 ◽  
Author(s):  
Xiebin Wang ◽  
Sergey Kustov ◽  
Jan Van Humbeeck
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Selective Laser Melting ◽  
Functional Properties ◽  
Complex Structures ◽  
Transformation Behavior ◽  
Laser Melting ◽  
Niti Shape Memory Alloys

Due to unique functional and mechanical properties, NiTi shape memory alloys are one of the most promising metallic functional materials. However, the poor workability limits the extensive utilization of NiTi alloys as components of complex shapes. The emerging additive manufacturing techniques provide high degrees of freedom to fabricate complex structures. A freeform fabrication of complex structures by additive manufacturing combined with the unique functional properties (e.g., shape memory effect and superelasticity) provide great potential for material and structure design, and thus should lead to numerous applications. In this review, the unique microstructure that is generated by selective laser melting (SLM) is discussed first. Afterwards, the previously reported transformation behavior and mechanical properties of NiTi alloys produced under various SLM conditions are summarized.

On the Properties of Ni-Rich NiTi Shape Memory Parts Produced by Selective Laser Melting

2012 ◽  
Author(s):  
Christoph Haberland ◽  
Horst Meier ◽  
Jan Frenzel
Keyword(s):  
Additive Manufacturing ◽  
Shape Memory ◽  
Selective Laser Melting ◽  
Functional Properties ◽  
Processing Route ◽  
Laser Melting ◽  
Elementary Processes ◽  
Near Net Shape ◽  
Manufacturing Technologies ◽  
Niti Shape Memory Alloys

Processing of Nickel-Titanium (NiTi) shape memory alloys (SMAs) is challenging because smallest compositional variances and all types of microstructural features strongly affect the elementary processes of the martensitic transformation and thus the functional properties of the material. Against this background, powder metallurgical near net shape methods are attractive for the production of NiTi components. Especially additive manufacturing technologies (AM) seem to provide high potential, although they have received only little attention for processing NiTi so far. This work is the first to report on pseudoelastic properties of additive manufactured Ni-rich NiTi. We show how to establish pseudoelasticity in NiTi samples prepared by the additive manufacturing technique Selective Laser Melting (SLM). Therefore, we analyze phase transformation behavior, mechanical characteristics and functional properties of our materials subjected to different heat treatments. The obtained results are compared to the behavior of conventional NiTi. The presented results clearly indicate that SLM provides a promising processing route for the fabrication of high quality NiTi parts.

scholarly journals Fused Filament Fabrication-4D-Printed Shape Memory Polymers: A Review

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 701
Author(s):  
Sara Valvez ◽  
Paulo N. B. Reis ◽  
Luca Susmel ◽  
Filippo Berto
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Shape Memory ◽  
Structural Integrity ◽  
Shape Memory Polymer ◽  
Shape Memory Polymers ◽  
Layer By Layer ◽  
4D Printing ◽  
Fused Filament Fabrication ◽  
External Stimuli

Additive manufacturing (AM) is the process through which components/structures are produced layer-by-layer. In this context, 4D printing combines 3D printing with time so that this combination results in additively manufactured components that respond to external stimuli and, consequently, change their shape/volume or modify their mechanical properties. Therefore, 4D printing uses shape-memory materials that react to external stimuli such as pH, humidity, and temperature. Among the possible materials with shape memory effect (SME), the most suitable for additive manufacturing are shape memory polymers (SMPs). However, due to their weaknesses, shape memory polymer compounds (SMPCs) prove to be an effective alternative. On the other hand, out of all the additive manufacturing techniques, the most widely used is fused filament fabrication (FFF). In this context, the present paper aims to critically review all studies related to the mechanical properties of 4D-FFF materials. The paper provides an update state of the art showing the potential of 4D-FFF printing for different engineering applications, maintaining the focus on the structural integrity of the final structure/component.

Sign in / Sign up

Export Citation Format

Share Document