A comparison of axial fatigue strength of coarse and ultrafine grain commercially pure titanium produced by ECAP

Naseri, Reza; Hiradfar, Hamed; Shariati, Mahmoud; Kadkhodayan, Mehran

doi:10.1016/j.acme.2017.12.005

Cited by 15 publications

(31 citation statements)

References 53 publications

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“…47 As a dental implant material, UFG-Ti should have an appropriate elastic modulus and ductility to prevent the stress shielding, which appeared at the implant/bone interface and influenced adversely on osseointegration. 48 Copper casing, 31 a low ECAP pressing speed, and proper annealing 19 were adopted in this study to keep the elastic modulus stable and the grain size uniform. The result showed the elastic modulus of UFG-Ti was approximately 102 GPa, equivalent to that of CP-Ti.…”

Section: Resultsmentioning

confidence: 99%

“…UFG-Ti was prepared by the ECAP method using CP-Ti grade 2 (Xi’an Aerospace New Material Co. Ltd., Shaanxi, China). To prevent cracks in the titanium rod during the pressing process, the rod was coated with a 2 mm thick layer of copper − and lubricated with Molybdenum disulfide (MoS 2 ). Then, the CP-Ti material was processed using 4 passes of ECAP in route B C where the sample was rotated along the longitudinal axis by 90° after each pass at room temperature and finally annealed at 300 °C for 1 h (Figure a).…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Fracture Strength and Osseointegration of an Ultrafine-Grained Titanium Mini Dental Implant after Macromorphology Optimization

Feng

Xin

et al. 2019

ACS Biomater. Sci. Eng.

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The aim of this in vitro and in vivo study was to evaluate the fracture strength and osseointegration of an ultrafine-grained pure titanium (UFG-Ti) mini dental implant, prepared by equal channel angular pressing (ECAP) after macro-morphology optimization. UFG-Ti was prepared by ECAP using four passes in route Bc with the internal channel angle of 120°at room temperature. Furthermore, its microstructure and mechanical properties were studied. In optimization, a three-dimensional finite element model (FEM) composed of an UFG-Ti mini implant and alveolar bone was established to improve the implant surface area and decrease the stress distribution. Then, optimized mini implants were fabricated using UFG-Ti, and a fracture strength test was performed. For the in vivo study, UFG-Ti mini implants were inserted into rabbit femurs. A histological assessment and a pullout test were performed to evaluate its osseointegration ability. The results show that the ultimate tensile strength of UFG-Ti (685 ± 35 MPa) was significantly higher than that of commercial pure titanium (CP-Ti grade 4, 454 ± 27 MPa). After optimization, the surface area of the 2.5 mm diameter mini implant was 19% higher than that of the standard-thread mini implant, and the maximum equivalent stress (Max EQV stress) decreased by 28% in cortical bone and by 33.1% in cancellous bone, when the thread height was 0.3 mm and the pitch was 0.67 mm. The fracture strength of the UFG-Ti mini implants (328 ± 21 N) was significantly higher than that of CP-Ti grade 4 mini implants (197 ± 11 N). The in vivo study showed favorable osseointegration in both the UFG-Ti and CP-Ti groups, but the osseointegration strength of the optimized mini implants was higher than that of the standard-thread mini implants. In conclusion, the fracture and osseointegration strength had been significantly improved for UFG-Ti mini dental implant after optimization. The excellent mechanical properties and osseointegration of the UFG-Ti mini implant suggest its feasibility for clinical application.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Fracture Strength and Osseointegration of an Ultrafine-Grained Titanium Mini Dental Implant after Macromorphology Optimization

Feng

Xin

et al. 2019

ACS Biomater. Sci. Eng.

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“…Одним из решений данной проблемы является использование технически чистого титана, подвергнутого деформационной упрочняющей обработке. Одним из приемов, приводящих к заметному повышению механических и усталостных свойств металлических материалов, является формирование ультрамелкозернистой (УМЗ) структуры [1][2][3]. Эффективным подходом к формированию УМЗ структуры является интенсивная пластическая деформация (ИПД), например равноканальное угловое прессование (РКУП), РКУП-Конформ [4].…”

Section: Introductionunclassified

“…Эффективным подходом к формированию УМЗ структуры является интенсивная пластическая деформация (ИПД), например равноканальное угловое прессование (РКУП), РКУП-Конформ [4]. Исследования показывают преимущества такого подхода для повышения механических свойств Ti и ряда титановых сплавов медицинского назначения [2][3][4]. Так, после РКУП в технически чистом титане формируется структура с размером зерен/субзерен порядка 200 нм, а предел прочности при этом возрастает с 700 до 1100 МПа [4].…”

Section: Introductionunclassified

Roughness and microhardness of UFG Grade 4 titanium under abrasive-free ultrasonic finishing

Asfandiyarov¹,

Raab²,

Гундеров³

et al. 2022

FMT

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Increasing the fatigue resistance of implants is an important scientific and technical problem. One of the solutions to this problem is the high-strength state formation due to the ultrafine-grained (UFG) structure. However, high-strength alloys are characterized by greater sensitivity to stress concentrators and the surface roughness parameter. In turn, implant designs, as a rule, imply the presence of concentrators in the form of various grooves, threaded elements, etc., and the manufacturing technology supposes mechanical processing with an ambiguous effect on a finished product surface. The application of additional surface finishing, for example, abrasive-free ultrasonic finishing (AFUF), is a solution to this problem. This work aims to study the effect of different AFUF modes on the microhardness and roughness of a cylindrical blank made of Grade 4 commercially pure titanium in the UFG state. During the study, the authors assessed the effect of the rotation frequency of a workpiece and the static force of pressing the tool against the processed workpiece on the surface parameters; carried out microstructural studies of the obtained samples. The results showed that processing titanium in the UFG state by the AFUF method leads to a significant increase in the surface microhardness and a decrease in its roughness. For example, depending on the mode, the increase in microhardness can reach from 2 to 3.5 times. The authors investigated the effect of a power level of ultrasonic treatment on roughness and microhardness and considered various variants of surface pretreatment. The study identified that an increase in the speed of rotation of a workpiece reduces the roughness of a machined workpiece, while the microhardness increases.

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“…12 Previous studies have been shown that strength of this pure material can be promoted close to the common medical Ti alloy (Ti–6Al–4V) by imposing ECAP. 8,13,15…”

Section: Introductionmentioning

confidence: 99%

Corrosion-fatigue resistance of ultrafine grain commercially pure titanium in simulated body fluid

Naseri

Hiradfar

Shariati

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part E:

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Commercially pure titanium (CP-Ti) due to excellent biocompatibility and high specific strength is known as a metallic biomaterial and is widely utilized in medical applications as implant material. Because of low strength of CP-Ti as compared to other bio-metals, it has been proved in literatures that applying equal channel angular pressing (ECAP) process can be useful to enhancement of mechanical and metallurgical properties of CP-Ti by improvement of initial microstructure to ultrafine grained (UFG). Implant in human body is attacked from cyclic fatigue loads and corrosion, simultaneous. Hence, aim of this study is examination of corrosion-fatigue resistance of CP-Ti before and after introducing ECAP in simulated body fluid (SBF) as a saline solution close to blood plasma. In this study, multi-pass ECAP is conducted on CP-Ti at room temperature and then the axial fatigue test is performed in SBF environment with temperature 37 °C. The comparison of stress-cycle curves demonstrated that corrosion-fatigue resistance of ECAPed CP-Ti is extremely higher than initial annealed one. Moreover, it was observed that by increasing the pass number of ECAP, corrosion-fatigue resistance improves significantly. Furthermore, these results are compared to fatigue behavior of CP-Ti in air environment. The results show that corrosion-fatigue resistance of unECAPed and ECAPed CP-Ti in SBF is slightly lower than fatigue ones in air. According to the results of this experimental research, it is concluded that UFG CP-Ti has an awesome corrosion-fatigue resistance in human body and it is very suitable for utilizing as material of implants.

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A comparison of axial fatigue strength of coarse and ultrafine grain commercially pure titanium produced by ECAP

Cited by 15 publications

References 53 publications

Fracture Strength and Osseointegration of an Ultrafine-Grained Titanium Mini Dental Implant after Macromorphology Optimization

Fracture Strength and Osseointegration of an Ultrafine-Grained Titanium Mini Dental Implant after Macromorphology Optimization

Roughness and microhardness of UFG Grade 4 titanium under abrasive-free ultrasonic finishing

Corrosion-fatigue resistance of ultrafine grain commercially pure titanium in simulated body fluid

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