Mechanical properties of environmental-electro-discharge-sintered porous Ti implants

An, Ying; Oh, N.H.; Chun, Yeyang; Kim, Y.H.; Kim, D.K.; Park, J.S.; Kwon, Jong Jin; Choi, Kyoung-Ho; Eom, Tae Gwan; Byun, T.H.; Kim, J.Y.; Reucroft, P. J.; Kim, K.J.; Lee, W.H.

doi:10.1016/j.matlet.2005.02.059

Cited by 40 publications

(16 citation statements)

References 7 publications

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“…These compacts exhibit only very fine pores and remnants of fine oxides on particle boundaries. The lower porosity in the central part of the compacts sintered at 900 C, observed also by An et al [18] who applied a somewhat different technique of powder consolidation, is due to a higher triaxiality in the middle of the pre-compacted specimen. Stress conditions due to triaxiality lead to an easier break up of the continuous oxide layer on the surface of the particles formed at this temperature [11] and consequently, a better electrical contact between particles and higher local current densities during SPS are achieved.…”

Section: Methodssupporting

confidence: 57%

Mechanical properties of spark plasma sintered FeAl intermetallics

et al. 2010

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Section: Methodssupporting

confidence: 57%

Mechanical properties of spark plasma sintered FeAl intermetallics

et al. 2010

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“…Within this context, many research works can currently be found dedicated to the development of new implant materials with a bone-matching modulus, such as metastable b-titanium alloys [12], magnesium and its alloys [13] and porous materials [14,15]. There are several manufacturing processes for the latter, among which are highlighted: the electron beam melting process [16], creep expansion of argon-filled pores [17], directional aqueous freeze casting [18], rapid prototyping techniques [19], laser-engineered net shaping [20], electric current activated/assisted sintering techniques [21,22], conventional powder metallurgy [23] and space-holder techniques [24]. In this last process, most of the space-holders (ammonium bicarbonate [25][26][27][28], carbamide [29] and PVA [30]) are completely evaporated at low temperatures, whilst others (e.g., sodium chloride [31][32][33][34][35]) are removed by a dissolution process, generally in water.…”

Section: Introductionmentioning

confidence: 99%

Processing, characterization and biological testing of porous titanium obtained by space-holder technique

et al. 2012

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The high Young's modulus of titanium with respect to that one of the bone is the main cause of the stressshielding phenomenon, which promotes bone resorption around implants. Development of implants with a low Young's modulus has gained increased importance during the last decade, and the manufacturing of porous titanium is one of the routes to reduce this problem. In this work, porous samples of commercially pure titanium grade IV obtained by powder metallurgy with ammonium bicarbonate (NH 4 HCO 3 ) as space-holder were studied. Evaluations of porosity and mechanical properties were used to determine the influence of compaction pressure for a fixed NH 4 HCO 3 content. Measurements by ultrasound tests gave Young's modulus results that were low enough to reduce stress shielding, whilst retaining suitable mechanical strength. Biological tests on porous cp Ti showed good adhesion of osteoblasts inside the pores, which is an indicator of potential improvement of osteointegration.

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“…[1][2][3][4] Several previous works showed that is possible to match the stiffness of cortical bone using different techniques to fabricate porous titanium samples. [5][6][7][8][9][10][11][12][13][14][15] However, there is a lack of studies about the real effect of this porosity on other important mechanical properties, i.e., mechanical strength and fatigue life, and about the relationships between both the porosity and microstructure with the mechanical properties. Porosity percentage must be controlled to reduce the implant stiffness without any undesirable influence in mechanical resistance.…”

Section: Introductionmentioning

confidence: 99%

Conventional Powder Metallurgy Process and Characterization of Porous Titanium for Biomedical Applications

Torres

Pavón

Nieto

et al. 2011

Metall Mater Trans B

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Commercially pure titanium (c.p. Ti) is one of the best metallic biomaterials for bone tissue replacement. However, one of its main drawbacks, which compromises the service reliability of the implants, is the stress-shielding phenomenon (Young's modulus mismatch with respect to that one of the bone). Several previous works attempted to solve this problem. One alternative to solve that problem has been the development of biocomposites implants and, more recently, the fabrication of titanium porous implants. In this work, porous samples of c.p. Ti grade 4 were obtained using conventional powder metallurgy technique. The influence of the processing parameters (compacting pressure and sintering temperature) on the microstructure features (size, type, morphology, and percentage of porosity), as well as on the mechanical properties (compressive yield strength, and conventional and dynamic Young's modulus) were investigated. The results indicated that there is an increment in density, roundness of pores, and mean free path between them as compacting pressure and/or sintering temperature is increased. The Young's modulus (conventional and dynamic) and yield strength showed the same behavior. Better stiffness results, in the central part of cylindrical samples, were obtained for a uniaxial compression of 38.5 MPa using a sintering temperature of 1273 K and 1373 K (1000°C and 1100°C). An evaluation of porosity and Young's modulus along a cylindrical sample divided in three parts showed that is possible to obtain a titanium sample with graded porosity that could be used to design implants. This approach opens a new alternative to solve the bone resorption problems associated with the stress-shielding phenomenon.

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Mechanical properties of environmental-electro-discharge-sintered porous Ti implants

Cited by 40 publications

References 7 publications

Mechanical properties of spark plasma sintered FeAl intermetallics

Mechanical properties of spark plasma sintered FeAl intermetallics

Processing, characterization and biological testing of porous titanium obtained by space-holder technique

Conventional Powder Metallurgy Process and Characterization of Porous Titanium for Biomedical Applications

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