Enhanced Sintering of TiNi Shape Memory Foams under Mg Vapor Atmosphere

Date

2012-12-01

Author

Aydoğmuş, Tarık
Bor, Sakir

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

216
views

0
downloads

TiNi alloy foams are promising candidates for biomaterials to be used as artificial orthopedic implant materials for bone replacement applications in biomedical sector. However, certain problems exist in their processing routes, such as formation of unwanted secondary intermetallic phases leading to brittleness and deterioration of shape memory and superelasticity characteristics; and the contamination during processing resulting in oxides and carbonitrides which affect mechanical properties negatively. Moreover, the eutectic reaction present in Ti-Ni binary system at 1391 K (1118 A degrees C) prevents employment of higher sintering temperatures (and higher mechanical properties) even when equiatomic prealloyed powders are used because of Ni enrichment of TiNi matrix as a result of oxidation. It is essential to prevent oxidation of TiNi powders during processing for high-temperature (> 1391 K i.e., 1118 A degrees C) sintering practices. In the current study, magnesium powders were used as space holder material to produce TiNi foams with the porosities in the range of 40 to 65 pct. It has been found that magnesium prevents secondary phase formation and contamination. It also prevents liquid phase formation while enabling employment of higher sintering temperatures by two-step sintering processing: holding the sample at 1373 K (1100 A degrees C) for 30 minutes, and subsequently sintering at temperatures higher than the eutectic temperature, 1391 K (1118 A degrees C). By this procedure, magnesium may allow sintering up to temperatures close to the melting point of TiNi. TiNi foams produced with porosities in the range of 40 to 55 pct were found to be acceptable as implant materials in the light of their favorable mechanical properties.

Subject Keywords

TiNTINI alloy; NITIO3; TINI powder; liquid phase formation, Porous niti, Mechanical-properties, High-porosity, Alloys, Behavior, Replication, Magnesium

URI

https://hdl.handle.net/11511/64804

Journal

METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE

DOI

https://doi.org/10.1007/s11661-012-1350-y

Collections

Department of Metallurgical and Materials Engineering, Article

Suggestions

OpenMETU
Core

Enhancing biocompatibility of tantalum via anodization for orthopedic applications Uslu, Ece; Ercan, Batur (null; 2018-12-06) Tantalum and its alloys have been investigated as the next generation of orthopedic implant materials in the last decade. Being a valve metal, tantalum forms a naturally occurring stable oxide layer approximately 3-5 nm on its surface at ambient conditions and this layer both prevents heavy ion release from the metal and provides a natural barrier for implant corrosion. In fact, due to its chemically inert nature, tantalum has the highest corrosion resistance of all metals used in orthopedic applications. T...
EMULSION-BASED PROCESSING AND CHARACTERIZATION OF BIOMIMETIC HYDROXYAPATITE MICROSPHERES BY USING CALCIUM PHOSPHATE CEMENTS Öndin, Nilsu; Durucan, Caner; Department of Metallurgical and Materials Engineering (2022-11-22) Synthetic materials for bone defects have been widely used for biomedical applications. One of these materials is bioactive ceramic-based microspheres in the size range of couple 100s m. These microspheres are used for irregular defect filling operations due to high packing efficiency. The spherical shape also increases the surface area, reactivity, and cell adhesion. The osteoconduction (bone tissue growth) is the primary concern for hard-tissue replacements and grafts. Alpha-tricalcium phosphate (-TCP, ...
Additive manufacturing of biodegradable magnesium implants and scaffolds: Review of the recent advances and research trends Sezer, Nurettin; Evis, Zafer; Koc, Muammer (2021-03-01) Synthetic grafting needs improvements to eliminate secondary surgeries for the removal of implants after healing of the defected tissues. Tissue scaffolds are engineered to serve as temporary templates, which support the affected tissue and gradually degrade through the healing period. Beside mechanical function to withstand the anatomic loading conditions, scaffolds should also provide a decent biological function for the diffusion of nutrients and oxygen to the cells, and excretion of the wastes from the ...
Comprehensive Evaluation of the Biological Properties of Surface-Modified Titanium Alloy Implants Piszczek, Piotr; Radtke, Aleksandra; Ehlert, Michalina; Jedrzejewski, Tomasz; Sznarkowska, Alicja; Sadowska, Beata; Bartmanski, Michal; Erdoğan, Yaşar Kemal; Ercan, Batur; Jedrzejczyk, Waldemar (2020-02-01) An increasing interest in the fabrication of implants made of titanium and its alloys results from their capacity to be integrated into the bone system. This integration is facilitated by different modifications of the implant surface. Here, we assessed the bioactivity of amorphous titania nanoporous and nanotubular coatings (TNTs), produced by electrochemical oxidation of Ti6Al4V orthopedic implants' surface. The chemical composition and microstructure of TNT layers was analyzed by X-ray photoelectron spec...
Enhancement of mechanical properties of co-doped hydroxyapatite coatings on pre-treated Ti6Al4V Hacıoğlu, Tuğçe; Evis, Zafer; Tezcaner, Ayşen (2017-10-27) Titanium and its alloys are commonly preferred implant materials for hard tissue applications. Today more than 4.4 million people have an internal fixation device and over 1.3 million people possess an artificial joint. Not only is there high demand for orthopedic surgeries for new patients every year, but there is also an even higher demand for patients who must receive revision surgeries. In order to enhance the properties of titanium based implant materials, different pretreatment and coating techniques ...

Citation Formats

T. Aydoğmuş and S. Bor, “Enhanced Sintering of TiNi Shape Memory Foams under Mg Vapor Atmosphere,” METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE, pp. 5173–5181, 2012, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/64804.