Hakan Yilmazer

Hakan Yilmazer
Yildiz Technical University · Department of Metallurgical and Materials Engineering

PhD

About

54
Publications
20,930
Reads
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624
Citations
Citations since 2016
24 Research Items
541 Citations
2016201720182019202020212022020406080100120140
2016201720182019202020212022020406080100120140
2016201720182019202020212022020406080100120140
2016201720182019202020212022020406080100120140
Introduction
Hakan Yilmazer currently works at the Department of Metallurgical and Materials Engineering, Yildiz Technical University. Hakan does research in Materials Science and Engineering. Their current theme is 'Titanium and its alloys, Biodegradable metallic materials, severe plastic deformation, surface modification of metalic materials'.
Additional affiliations
March 2015 - present
Yildiz Technical University
Position
  • Professor (Assistant)
October 2012 - October 2015
Tohoku University
Position
  • PostDoc Position
Description
  • Niinomi Laboratory, Division of Biomaterials Research,
October 2008 - April 2012
Tohoku University
Position
  • Research Assistant
Education
October 2008 - September 2012
Tohoku University
Field of study
  • Materials Science
September 2006 - August 2008
Istanbul Technical University
Field of study
  • Metallurgical and Materials Engineering
September 2001 - June 2006
Istanbul Technical University
Field of study
  • Metallurgical and Materials Enginering

Publications

Publications (54)
Article
Full-text available
Diabetic wounds are very problematic wounds that have a high risk of infection. The healing process of wounds in diabetic patients is more complicated than others. Wound dressing preparation is one of the promising treatment modalities for repairing damaged tissues in diabetic patients. The aim of this study is to demonstrate the antibacterial effe...
Article
A non-toxic and non-allergic β-type Ti–29Nb–13Ta-4.6Zr (hereafter abbreviated as TNTZ) target material was prepared by the vacuum arc-melting process and then hot-forged, successfully. The TNTZ target has been deposited on the pure magnesium (Mg) and AZ31 Mg alloys by the physical vapor deposition (PVD) method. The characterization of the coatings...
Article
Full-text available
In this study, a novel Polyvinyl Alcohol (PVA)/Hexagonal Boron Nitride (hBN)/Bacterial Cellulose (BC) composite, bone tissue scaffolds were fabricated using 3D printing technology. The printed scaffolds were characterized by fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), tensile testing, swelling behaviour, dif...
Article
Full-text available
Absorbable metals have the potential to serve as the next generation of temporary medical implant devices by safely dissolving in the human body upon vascular tissue healing and bone regeneration. Their implementation in the market could greatly reduce the need of costly and risky additional surgeries for either implant replacement or removal, ofte...
Article
High-pressure torsion (HPT) was used to investigate the potential of grain refinement and strengthening achievable for aluminum alloy 2139-T8. Discs of 20 mm diameter and approximately 0.9 mm thickness were HPT processed at room temperature under an applied pressure of 5 GPa after 1, 2, 4 and 8 revolutions. Microstructural characterization of the H...
Article
Full-text available
High-pressure torsion (HPT) was used to investigate the synthesis of Zn-Mg hybrids by direct bonding of separate disks of Zn and Mg at room temperature under an applied pressure of 6.0 GPa after 1, 5, 15 and 30 turns. Microstructural characterisation of the HPT-processed disks showed the formation of a sub-micron multilayered structure embedded in...
Article
Full-text available
The bioprinting process describes as computer-assisted material transfer process of biological structures such as cells and biomaterials to fabricate medical constructions for different medical fields (scaffolds engineering, tissue renewal, and etc.). Especially, 3D (Three-Dimension) bioprinting technology is used to print living organs like livers...
Article
In this study, hydroxyapatite (HA) based composite films were successfully syntheses on the β-type Ti29Nb13Ta4.6Zr (TNTZ). The solutionized TNTZ substrates coated with HA and HA/Titania (TiO2) bioactive composite coatings by sol-gel method under various sintering parameters related to sintering temperatures and heating ramp rates. Microstructural o...
Conference Paper
The bio-printing process describes as a computer-aided transfer process for printing of biological structures such as cells and biomaterials to fabricate medical constructions for different medical fields (tissue engineering, regenerative medicine, or other biological studies). Especially, three-dimension (3D) bioprinting technology is used to prin...
Article
Full-text available
Titanium (Ti) and Ti alloys most frequently used metallic biomaterials in implant due to low elastic modulus, high strength, good biocompatibility and higher corrosion resistance. In this study; hydroxyapatite (HA:Ca5(PO4)3(OH)) based bioactive hybrid coatings reinforced with zirconia (ZrO2) has been successfully synthesized by sol-gel technique on...
Article
The microstructural evolution and its effect on biocompatibility of TNTZ through HPT processing were investigated systematically in this study. TNTZAHPT shows an enhanced mechanical biocompatibility, which is characterized by a higher tensile strength (1375 MPa) and hardness (450 HV) than those of TNTZST, TNTZAT, and Ti64 ELI while maintaining a re...
Conference Paper
Full-text available
A biocomposite coating containing chitosan and hydroxyapatite was developed on Ti-6Al-4V substrate by a sol-gel method in order to obtain a biocompatible and antimicrobial implant surface which can be used to create a smooth transmucosal region for a faster and better wound healing and an increased bioactivity. The coatings characterized by scannin...
Conference Paper
Titanium (Ti) and Ti alloys most frequently used metallic biomaterials in implant due to low elastic modulus, high strength, good biocompatibility and higher corrosion resistance. In this study; hydroxyapatite (HA: Ca5(PO4)3(OH)) based bioactive hybrid coatings reinforced with zirconia (ZrO2) has been successfully synthesized by sol-gel technique o...
Conference Paper
Full-text available
Hydroxyapatite (HA) and HA/titania (TiO2) hybrid films were successfully syntheses on Ti29Nb13Ta4.6Zr (TNTZ) alloys using sol-gel method. Titanium alloys coated with HA/TiO2 by dip-coating technique, followed by a sintering at 600, 700 and 800 °C for 120 min. Results indicating that doping of HA with TiO2, enhanced the chemical affinity and the phy...
Conference Paper
Literatürde α veya α+β tipi çok farklı titanyum alaşımlarına ticari biyomedikal uygulamalarda rastlamak mümkündür ve bu alaşımların mekanik, korozif yada karakterizasyonu üzerine birçok çalışmaya rastlanabilir. Ancak, bu materyallerin, biyomalzeme olarak kullanabilmesi için en önemli dezavantajları kemiğe göre çok yüksek elastik modüle sahip olmala...
Article
Full-text available
Ultrafine-grained materials often possess superior mechanical properties owing to their small grain size. The high-pressure torsion (HPT) process is a severe plastic deformation method used to induce ultra-large strain and produce ultrafine grains. In this study, the grain refinement mechanisms in the Co–28Cr–6Mo (CCM) alloy, evolution of dislocati...
Chapter
Biomedical Ti-29Nb-13Ta-4.6Zr (TNTZ) has been developed as a structural material for implant devices. Mcrostructural refinement of TNTZ and its effect on mechanical biocompatibility and surface functionality through HPT processing are investigated systematically in this study. Aged TNTZ subjected to HPT processing (TNTZAHPT) has a homogeneous micro...
Article
The combined effects of process gases and post-heat treatment temperature on the microstructure of 316L cold-sprayed coatings on Al5052 substrates have been investigated in this study. The stainless steel coatings were subjected to heat treatment at four different temperatures (250, 500, 750, and 1000 °C) to study the effect of heat treatment. In a...
Article
Proper surface characteristic for a titanium implant is crucial for the formation of different cellular protrusions known as filopodia and lammellipodia, both of which have a significant impact on cell attachment, spreading, migration, and proliferation. Microstructural features such as grain boundaries and defects of implant surface can modulate t...
Article
Full-text available
Abstract The effects of severe plastic deformation through high-pressure torsion (HPT) on the microstructure and tensile properties of a biomedical Co-Cr-Mo (CCM) alloy were investigated. The microstructure was examined as a function of torsional rotation number, N and equivalent strain, εeq in the HPT processing. Electron backscatter diffraction a...
Article
In order to elucidate the microstructural refinement mechanism and the effect of secondary phase on the microstructural evolution of β-type titanium alloy, severe plastic deformation was conducted on samples of a precipitation-hardened Ti–29Nb–13Ta–4.6Zr (TNTZ). Specifically, TNTZ that was precipitation-hardened through an aging treatment (TNTZAT)...
Article
A novel β-type titanium alloy Ti-29Nb-13Ta-4.6Zr (TNTZ) has been developed and extensively researched to achieve highly desirable mechanical properties such as a high strength while maintaining a low Young's modulus that is close to that of bone, as an alternative candidate for conventional titanium metallic biomaterials such as Ti-6Al-4V ELI. Ther...
Article
Full-text available
The effect of high-pressure torsion (HPT) processing on the microstructure and Vickers hardness of Co-Cr-Mo (CCM) alloys were investigated in this study. The microstructure of initial CCM alloy contains equiaxed grains with a grain diameter of approximately 50 μm and twins. The clear grain boundaries of equiaxed grains and twins disappear after HPT...
Article
Full-text available
A novel β-type, Ti-29Nb-13Ta-4.6Zr, referred to as TNTZ has been developed for biomedical applications. Its fatigue strength is one of the most important mechanical biocompatibilities of TNTZ because, in surgical applications, it will be used under cyclic loading conditions. The effect of the microstructural refinement by high-pressure torsion (HPT...
Article
A novel β-type titanium alloy (Ti-29Nb-l 3 Ta-4.6Zr, TNTZ) has been developed as a candidate for biomedical applications. In this study, the effect of high-pressure torsion (HPT) on the corrosion behaviors of TNTZ after cold rolling (CR) and aging treatment (AT) was investigated under in-vitro conditions by potentiodynamic polarization technique (P...
Article
The effect of high-pressure torsion (HPT) processing on the microstructure and mechanical biocompatibility includes Young's modulus, tensile strength, ductility, fatigue life, fretting fatigue, wear properties and other functionalities such as super elasticity and shape memory effect, etc. at levels suitable for structural biomaterials used in impl...
Article
The biomedical β -type titanium alloy Ti–29Nb–13Ta–4.6Zr (TNTZ) exhibits non-toxicity and a low Young’s modulus that is similar to that of bone. This alloy has a low Young’s modulus because it contains a metastable β phase. Strengthening due to grain refinement tends to provide high mechanical strength, while keeping the Young’s modulus low, becaus...
Conference Paper
A novel β-type titanium alloy (Ti-29Nb-13Ta-4.6Zr, TNTZ) has been developed as a candidate for biomedical applications. High-pressure torsion (HPT) is one of the effective ways to obtain high mechanical strength and low Young’s modulus in TNTZ alloys. In this study, the effect of HPT on the corrosion behaviour of TNTZ after aging treatment was inve...
Article
The effect of high-pressure torsion (HPT) processing on the microstructure of a novel Ti-29Nb-13Ta-4.6Zr (TNTZ) after cold-rolling and aging treatment for biomedical applications was systematically investigated in this study. Cold-rolled TNTZ subjected to HPT processing (TNTZ_ ) at low N exhibits a heterogeneous microstructure in micro-scale and na...
Article
A novel -type titanium alloy, Ti–29Nb–13Ta–4.6Zr (TNTZ), has been developed as a candidate for biomedical applications. TNTZ exhibits non-toxicity and a low Young’s modulus close to that of bone (10–30 GPa). Such a low Young’s modulus of this alloy is achieved by comprising a single metastable phase. Greater mechanical biocompatibility, which impli...
Article
High mechanical biocompatibility, which implies excellent mechanical properties such as great strength and hardness with keeping low Young's modulus in a new biomedical β-type titanium alloy, Ti-29Nb-13Ta-4.6Zr (TNTZ), can be achieved by microstructural control. Strengthening of TNTZ by grain refinement and increasing dislocation density is expecte...
Article
Strengthening by grain refinement and increasing dislocation density through high-pressure torsion (HPT), which is an attractive technique to fabricate ultrafine grained and nanostructured metallic materials, is expected to provide beta-type Ti-29Nb-13Ta-4.6Zr (TNTZ) higher mechanical strength while maintaining low Young's modulus because they keep...
Article
The mechanical properties and microstructure of commercial Al–15Si–2.5Cu–0.5Mg (Alumix-231®) alloy was subjected to extrusion (EXTR), hot extrusion into rods at 565∘C at an extrusion ratio of 4:1 and high-pressure torsion (HPT) processing, one of the most severe plastic deformation (SPD) techniques, with an anvil rotation speed of 0.5rpm under a qu...
Article
A new biomedical β-type titanium alloy, Ti-29Nb-13Ta-4.6Zr (TNTZ) has been developed by the authors. Severe plastic deformation (SPD) is a well-proved technique for forming submicron- or nano-sized grain structures in metallic materials. The effect of high-pressure torsion (HPT) processing on the microstructure and the mechanical properties of TNTZ...
Article
Full-text available
In order to improve the poor surface hardness and the wear resistance, titanium has been nitrided with plasma (ion) nitriding which is one of the methods to treat surface properties of titanium alloys. The increment at surface hardness and so the wear resistance of nitrided titanium alloys has been provided by means of compound layer (ε-Ti2N+δ-TiN)...

Questions

Questions (5)
Question
We are building a binder jetting 3D printer. We are looking for companies to buy thermo-responsive binders and dispenser or dispensing array with dispensing at 30-80 picoliter level.
Question
We were carried the Potentio-Dynamic Scanning for Ti-6Al-4V to evaluate its corrosion behavior. We observed a peak around 1.5 mV in the attached figure. What happen at this peak. Could you help me to define this peak, please?    
Best Regards
Question
I have been doing some corrosion experiments for Ti and its alloys, recently. 
I read the following paper. It is interesting and useful for the pitting morphology investigations. 
Could you explain about the polishing in ethanol which you mentioned in following parts of this paper?
" After samples were exposed to the two environments for 60 h, the corroded samples were cut by a diamond saw to observe their cross sections, and ethanol was sprayed to prevent further corrosion from occurring at the same time. The samples were polished with a series of emery papers to 4000 grit by hand, with continued spraying of 100% ethanol."
"Before doing the EDS test, specimens were hand polished with ethanol using the emery paper, without mounting or applying any alumina suspension."
Why would you do polishing in ethanol?
Is using just water not good for metallic materials?
Is it because of the Mg alloy? How about for Ti? 
Best Regards
Question
I am studying on microstructural control of beta type titanium alloys subjected to some deformation. I am going to evaluate surface energy of my samples using sessile drop contact angle measurements on mirror-like surfaces (no roughness effect). 
My question is how the following microstructural features effect on the surface energy?
- Grain size
- Grain boundaries (volume fraction, equilibrium and non-equilibrium state etc.)
- Dislocations
- Precipitated phase (size, volume fraction, and distribution ) 
Best Regards
Question
I would like to calculate surface energy of beta type titanium alloys using Kitazaki-Hata approach (Extended Fawkes). Most of studies are on polymer surface. And I saw the followings in most studies;
Water
Diiodomethane
Hexadecane
For titanium surface, which solvents do you recommend?
How about alkanes ( - Hexane - Dodecane - Tetradecane - Octane - Decane)?
Best Regards

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