Characterization of the hydroxyapatite layer formed by fine hydroxyapatite particle peening and its effect on the fatigue properties of commercially pure titanium under four-point bending

Kikuchi, Shoichi; Yoshida, Sho; Nakamura, Yuki; Nambu, Koichiro; Akahori, Toshikazu

doi:10.1016/j.surfcoat.2016.01.023

Cited by 37 publications

(15 citation statements)

References 27 publications

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“…CP titanium is of particular interest in this regard since it exhibits good biocompatibility and high corrosion resistance, and does not contain toxic elements such as Cr, Al or V. However, this material has lower tensile strength and fatigue strength than titanium alloys [1][2][3][4], and so improving the mechanical properties of CP titanium has become an important topic. The mechanical properties of metallic materials are affected by their microstructure, and grain refinement has been shown to be an effective method for increasing the strength of CP titanium [4,[8][9][10][11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

“…Another important aspect of the mechanical properties of biomaterials is fatigue resistance, which is dependent on the microstructure and stress ratio (the ratio of the minimum to the maximum stress) [4,[10][11][12][13][28][29][30][31][32][33][34][35][36][37][38][39]. Kitahara et al [11] determined that the characteristics of fatigue crack propagation in CP titanium are affected by the microstructure, and that the threshold stress intensity range, Kth, decreases as the grain size decreases with increasing number of accumulative roll bonding cycles.…”

Section: Introductionmentioning

confidence: 99%

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Evaluation of near-threshold fatigue crack propagation in harmonic-structured CP titanium with a bimodal grain size distribution

Kikuchi

Mori

Kubozono

et al. 2017

Engineering Fracture Mechanics

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To examine near-threshold fatigue crack propagation in commercially pure (CP) titanium with a bimodal harmonic structure, which is defined as a coarse grained structure surrounded by a network of fine grains, K-decreasing tests were conducted. The crack growth rates for harmonic-structured CP titanium were higher than those for homogeneous material with coarse grains at comparable stress intensity range, while the threshold stress intensity range was lower. This phenomenon was attributed to a reduction in the extent of crack closure and the effective threshold stress intensity range, resulting from the presence of fine grains in the harmonic structure.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Evaluation of near-threshold fatigue crack propagation in harmonic-structured CP titanium with a bimodal grain size distribution

Kikuchi

Mori

Kubozono

et al. 2017

Engineering Fracture Mechanics

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“…SP is also applied to pure titanium for medical use. Kikuchi et al applied fine hydroxyapatite particle peening to commercially pure Ti and demonstrated that hydroxyapatite layer was successfully formed on the surface and fatigue properties were improved . Ultrasonic shot peening (USP) is a kind of SP processes, in which ultrasonic vibration induces impact energy of shot media.…”

Section: Introductionmentioning

confidence: 99%

EBSD‐assisted fractography of sub‐surface fatigue crack initiation mechanism in the ultrasonic‐shot‐peened βeta‐type titanium alloy

Uematsu

Kakiuchi

Hattori

2018

Fatigue Fract Eng Mat Struct

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β‐type titanium alloy was surface treated by an ultrasonic shot peening (USP) process. Rotating bending fatigue tests were conducted to investigate the effect of USP on the fatigue properties. Fatigue strengths were improved by USP in the finite life region (105‐107 cycles) owing to the high hardness and compressive residual stress in the surface layer. However, the fatigue strengths of the as‐received and USPed specimens were nearly comparable in very high cycle fatigue (VHCF) regime around 108 cycles. The similar fatigue strengths in both specimens in VHCF regime were attributed to the sub‐surface crack initiation in the USPed specimen. The crack initiation site near the center of fisheye was flat, and inclusions were not observed. Phase analyses by EBSD showed that the microstructure of the as‐received material consisted of α‐phase rich and α‐phase poor β grains. Sub‐surface crack initiated at the α‐phase rich β grain, and consequently the sub‐surface crack initiation without inclusions was attributed to the inhomogeneity of microstructure.

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“…In this study, fine particle peening (FPP) treatment was applied for titanium alloy because the FPP treatment can improve the fatigue strength of metallic materials. In addition, the FPP treatment can create transferred layer consisted shot particle [4]- [6]. Thus, it is expected that the FPP treatment using hydroxyapatite shot particles can improve the fatigue strength and create HAp layer on the substrate.…”

Section: Introductionmentioning

confidence: 99%

Effect of Fine Particle Peening Using Hydroxyapatite Shot Particles and Plasma Sprayed Hydroxyapatite Coating on Fatigue Properties of Beta Titanium Alloy

Nakamura¹,

Aoki²,

Shimizu³

et al. 2017

WIT Transactions on Engineering Sciences

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Fine particle peening (FPP) and plasma spraying using hydroxyapatite particles were applied to a beta titanium alloy, Ti-22V-4Al, to form the hydroxyapatite (HAp) layer on the surface. As a result, HAp layer was formed on the specimen surface by the both treatments. The thicknesses were 5 m and 100m, respectively for FPP treated and plasma sprayed specimens. In the FPP treated specimen, Vickers hardness was increased by FPP compared with that of the untreated specimens, resulting in work-hardening. Rotary bending fatigue tests were carried out on both treated and untreated specimens. The FPP treated specimens exhibited higher fatigue strength than the untreated specimens. It is due to the increase in hardness and compressive residual stress by FPP. On the other hand, significant deteriorations of the fatigue strength for the plasma sprayed specimen was observed in comparison with the result for the untreated specimen. As a result of fracture surface observation in plasma sprayed specimen, the defect formed by blasting before the plasma spraying at interface between substrate and HAp layer was observed at crack initiation site. Thus, the defect plays a role as the crack starter in the case of plasma sprayed specimen. Keywords: fatigue, fine particle peening, plasma spray, titanium alloy, hydroxyapatite. INTRODUCTIONTitanium alloys have been used as implant components due to their high corrosion resistance, good biological compatibility and so on. In recent years, plasma and thermal spraying have been applied for titanium alloy to form the hydroxyapatite (HAp) layer on the surface and to improve osteo-conductivity [1]- [3]. However, Laonapakul et al. reported that delamination and spallation of the coating layer formed by plasma spraying occur under cyclic loading [3]. In this study, fine particle peening (FPP) treatment was applied for titanium alloy because the FPP treatment can improve the fatigue strength of metallic materials. In addition, the FPP treatment can create transferred layer consisted shot particle [4]- [6]. Thus, it is expected that the FPP treatment using hydroxyapatite shot particles can improve the fatigue strength and create HAp layer on the substrate.The aim of this study is to form HAp transferred layer on the substrate by FPP and to compare the fatigue strength of FPP using HAp particles treated specimen and HAp coated specimen by plasma spraying. Rotating bending fatigue tests were carried out for FPP treated specimens. Tests were also conducted on untreated specimens and hydroxyapatite coated specimens by plasma spraying for comparison. Fracture surface of all the failed specimens were examined in a scanning electron microscope (SEM). The effects of FPP and plasma spray on fracture mechanisms are also discussed in the light of fractography.

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Characterization of the hydroxyapatite layer formed by fine hydroxyapatite particle peening and its effect on the fatigue properties of commercially pure titanium under four-point bending

Cited by 37 publications

References 27 publications

Evaluation of near-threshold fatigue crack propagation in harmonic-structured CP titanium with a bimodal grain size distribution

Evaluation of near-threshold fatigue crack propagation in harmonic-structured CP titanium with a bimodal grain size distribution

EBSD‐assisted fractography of sub‐surface fatigue crack initiation mechanism in the ultrasonic‐shot‐peened βeta‐type titanium alloy

Effect of Fine Particle Peening Using Hydroxyapatite Shot Particles and Plasma Sprayed Hydroxyapatite Coating on Fatigue Properties of Beta Titanium Alloy

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