Fabrication of NiTi alloy: A review

Author(s):  
Neeraj Sharma ◽  
Kamal K Jangra ◽  
Tilak Raj

Nitinol (NiTi) is categorized as a smart material which is highly recognized material for medical and other engineering applications. The behaviour of NiTi can be modified by altering the composition, modifying the porosity and applying external thermal and mechanical treatment. Due to high composition sensitivity, there are several impediments in fabrication of NiTi with conventional techniques which impel the use of additive manufacturing methods. But due to very high cost of equipments, these processes have not been commercialized till now. This paper presents a review on applications, manufacturing NiTi alloy and its various production routes from conventional to rapid prototyping, porous NiTi, effect of additives on properties of the alloy and its challenges.

Author(s):  
Neeraj Sharma ◽  
Kamal Kumar

Nitinol has growing applications in aerospace industries, MEMS, and bio-medical industries due to its unique properties of pseudo-elasticity, bio-compatibility, and shape-memory effect. Behaviour of NiTi alloy can be changed by altering the composition, modifying the porosity, and applying external thermal and mechanical treatment. In this chapter, porous NiTi alloy with powder metallurgy is fabricated by varying the composition of polypropylene as an organic binder from 0% to 15%, and Young's modulus and porosity of porous alloy has been evaluated. The effect of process parameters—compaction pressure, sintering temperature, and sintering time—are evaluated using Taguchi L16 orthogonal array. These particles initially act as a binder but with the increase of temperature, the organic particles evaporate and create pores. With the increase of organic particle percentage, the porosity increases while Young's modulus decreases. SEM was used to characterize the fabricated porous NiTi alloy.


2021 ◽  
Author(s):  
Alexey Pustovarenko ◽  
Beatriz Seoane ◽  
Edy Abou-Hamad ◽  
Helen E King ◽  
Bert Weckhuysen ◽  
...  

3D printing, also known as additive manufacturing technology, has greatly expanded across multiple sectors of technology replacing classical manufacturing methods by combining processing speed and high precision. The scientific interest...


2013 ◽  
Vol 315 ◽  
pp. 63-67 ◽  
Author(s):  
Muhammad Fahad ◽  
Neil Hopkinson

Rapid prototyping refers to building three dimensional parts in a tool-less, layer by layer manner using the CAD geometry of the part. Additive Manufacturing (AM) is the name given to the application of rapid prototyping technologies to produce functional, end use items. Since AM is relatively new area of manufacturing processes, various processes are being developed and analyzed for their performance (mainly speed and accuracy). This paper deals with the design of a new benchmark part to analyze the flatness of parts produced on High Speed Sintering (HSS) which is a novel Additive Manufacturing process and is currently being developed at Loughborough University. The designed benchmark part comprised of various features such as cubes, holes, cylinders, spheres and cones on a flat base and the build material used for these parts was nylon 12 powder. Flatness and curvature of the base of these parts were measured using a coordinate measuring machine (CMM) and the results are discussed in relation to the operating parameters of the process.The result show changes in the flatness of part with the depth of part in the bed which is attributed to the thermal gradient within the build envelope during build.


2012 ◽  
Vol 70 ◽  
pp. 142-145 ◽  
Author(s):  
Muhammad Hussain Ismail ◽  
Russell Goodall ◽  
Hywel A. Davies ◽  
Iain Todd

Author(s):  
Matthew N. Rush ◽  
Christina Salas ◽  
Lorraine Mottishaw ◽  
Damian Fountain ◽  
Deana Mercer

Abstract Background Ligament reconstruction, as a surgical method used to stabilize joints, requires significant strength and tissue anchoring to restore function. Historically, reconstructive materials have been fraught with problems from an inability to withstand normal physiological loads to difficulties in fabricating the complex organization structure of native tissue at the ligament-to-bone interface. In combination, these factors have prevented the successful realization of nonautograft reconstruction. Methods A review of recent improvements in additive manufacturing techniques and biomaterials highlight possible options for ligament replacement. Description of Technique In combination, three dimensional-printing and electrospinning have begun to provide for nonautograft options that can meet the physiological load and architectures of native tissues; however, a combination of manufacturing methods is needed to allow for bone-ligament enthesis. Hybrid biofabrication of bone-ligament tissue scaffolds, through the simultaneous deposition of disparate materials, offer significant advantages over fused manufacturing methods which lack efficient integration between bone and ligament materials. Results In this review, we discuss the important chemical and biological properties of ligament enthesis and describe recent advancements in additive manufacturing to meet mechanical and biological requirements for a successful bone–ligament–bone interface. Conclusions With continued advancement of additive manufacturing technologies and improved biomaterial properties, tissue engineered bone-ligament scaffolds may soon enter the clinical realm.


2021 ◽  
Vol 58 (3) ◽  
pp. 198-209
Author(s):  
Vasile Cojocaru ◽  
Doina Frunzaverde ◽  
Dorian Nedelcu ◽  
Calin-Octavian Miclosina ◽  
Gabriela Marginean

Initially developed as a rapid prototyping tool for project visualization and validation, the recent development of additive manufacturing (AM) technologies has led to the transition from rapid prototyping to rapid manufacturing. As a consequence, increased attention has to be paid to the mechanical, chemical and physical properties of the printed materials. In mechanical engineering, the widespread use of AM technologies requires the optimization of process parameters and material properties in order to obtain components with high, repeatable and time-stable mechanical properties. One of the main problems in this regard is the anisotropic behavior of components made by additive manufacturing, determined by the type of material, the 3D printing technology, the process parameters and the position of the components in the printing space. In this paper the influence of the printing orientation angle on the tensile behavior of specimens made by material jetting is investigated. The aim was to determine if the positioning of components at different angles relative to the X-axis of the printer (and implicitly in relation to the multijet printing head) contributes to anisotropic behavior. The material used was a photopolymer with a mechanical strength between 40 MPa and 55 MPa, according to the producer. Four sets of tensile test specimens were manufactured, using flat build orientation and positioned on the printing table at angles of 0˚, 30˚, 60˚ and 90˚ to the X-axis of the printer. Comparative analysis of the mechanical behavior was carried out by tensile tests and microscopic investigations of the tensile test specimens fracture surfaces.


Author(s):  
Ivan Molnár ◽  
Ladislav Morovič

Abstract The paper discusses the use of 3D digitization and additive manufacturing technologies in the field of medicine. In addition, applications of the use of 3D digitization and additive manufacturing methods are described, focusing on the design and manufacture of individual medical aids. Subsequently, the process of designing and manufacturing of orthopedic aids using these technologies is described and the advantages of introducing the given technologies into the design and manufacturing processes in the medicine sector are presented.


Author(s):  
Bahram Raad ◽  
Narges Shayesteh Moghaddam ◽  
Mohammad Elahinia

The aim of this article is to investigate the effect of two different fixation hardware materials on bone remodeling after a mandibular reconstruction surgery and to restore the mandible’s function, healthy appearance, mastication, swallowing, breathing, and speech. The hypothesis is that using fixation hardware with stiffness close to that of the surrounding bone will result in a more successful healing process in the mandible bone. The finite element model includes the material properties and forces of the cancellous bone, cortical bone, ligaments, muscles, and teeth. The reconstruction surgery is modeled by including the fixation hardware and the grafted bone. In the sectioned mandible, to best mimic the geometry of the mandible, two single barrel grafts are placed at the top of each other to form a double barrel graft set. Two different materials were used as the mandibular fixation parts, stiff Ti-6Al-4V, and porous superelastic Nickel-Titanium (NiTi) alloys. A comparison of these two alloys demonstrates that using porous NiTi alloy as the fixation part results in a faster healing pace. Furthermore, the density distribution in the mandibular bone after the healing process is more similar to the normal mandible density distribution. The simulations results indicate that the porous superelastic NiTi fixation hardware transfers and distributes the existing forces on the mandible bone more favorably. The probability of stress shielding and/or stress concentration decrease. This type of fixation hardware, therefore, is more appropriate for mandible bone reconstruction surgery.


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