H. Özkan Gülsoy

Particle morphology influence on mechanical and biocompatibility properties of injection molded Ti alloy powder

Titanium and Titanium alloys exhibits properties that are excellent for various bio-applications. Metal injection molding is a processing route that offers reduction in costs, with the added advantage of near net-shape components. Different physical properties of Titanium alloy powders, shaped and processed via injection molding can achieve high complexity of part geometry with mechanical and bioactivity properties, similar or superior to wrought material. This study describes that the effect of particle morphology on the microstructural, mechanical and biocompatibility properties of injection molded Ti-6Al-4V (Ti64) alloy powder for biomaterials applications. Ti64 powders irregular and spherical in shape were injection molded with wax based binder. Binder debinding was performed in solvent and thermal method. After debinding the samples were sintered under high vacuum. Metallographic studies were determined to densification and the corresponding microstructural changes. Sintered samples were immersed in a simulated body fluid (SBF) with elemental concentrations that were comparable to those of human blood plasma for a total period of 15 days. Both materials were implanted in fibroblast culture for biocompatibility evaluations were carried out. The results show that spherical and irregular powder could be sintered to a maximum theoretical density. Maximum tensile strength was obtained for spherical shape powder sintered. The tensile strength of the irregular shape powder sintered at the same temperature was lower due to higher porosity. Finally, mechanical tests show that the irregular shape powder has lower mechanical properties than spherical shape powder. The sintered irregular Ti64 powder exhibited better biocompatibility than sintered spherical Ti64 powder. Results of study showed that sintered spherical and irregular Ti64 powders exhibited high mechanical properties and good biocompatibility properties.

Effect of Zr, Nb and Ti addition on injection molded 316L stainless steel for bio-applications: Mechanical, electrochemical and biocompatibility properties.

The research investigated the effect of Zr, Nb and Ti additions on mechanical, electrochemical properties and biocompatibility of injection molded 316L stainless steel. Addition of elemental powder is promoted to get high performance of sintered 316L stainless steels. The amount of additive powder plays a role in determining the sintered microstructure and all properties. In this study, 316L stainless steel powders used with the elemental Zr, Nb and Ti powders. A feedstock containing 62.5 wt% powders loading was molded at different injection molded temperature. The binders were completely removed from molded components by solvent and thermal debinding at different temperatures. The debinded samples were sintered at 1350°C for 60 min. Mechanical, electrochemical property and biocompatibility of the sintered samples were performed mechanical, electrochemical, SBF immersion tests and cell culture experiments. Results of study showed that sintered 316L and 316L with additives samples exhibited high corrosion properties and biocompatibility in a physiological environment.

Physical and Mechanical Properties of Iron Powder Filled Polystyrene Composites

This article reports on an experimental study of the physical and mechanical properties of Polystyrene (PS) and Fe-PS polymer composites containing 5, 10, and 15 vol.% of Fe powder. After mixing Fe powder and PS in a twin-screw extruder, an injection-molding machine was used to prepare unfilled PS and Fe-PS polymer composite samples. After that, the material properties were experimentally determined for each sample. The investigated material properties included the modulus of elasticity, yield and tensile strength, % elongation, Izod impact strength (notched), hardness (Shore D), melt flow index (MFI), heat deflection temperature (HDT), Vicat softening point, and glass transition temperature (T g ). The results indicated that, compared to the unfilled PS, an addition of Fe into PS decreases the yield and tensile strength, % elongation, and Izod impact strength. Furthermore, it was determined that the Fe particles increase the modulus of elasticity, hardness, MFI, Vicat softening point, and HDT values.

Effect of boron addition on injection molded 316L stainless steel: mechanical, corrosion properties and in vitro bioactivity.

The research was investigated the effect of boron additions on sintering characteristics, mechanical, corrosion properties and biocompatibility of injection molded austenitic grade 316L stainless steel. Addition of boron is promoted to get high density of sintered 316L stainless steels. The amount of boron plays a role in determining the sintered microstructure and all properties. In this study, 316L stainless steel powders have been used with the elemental NiB powders. A feedstock containing 62.5 wt% powders loading was molded at different injection molded temperature. The binders were completely removed from molded components by solvent and thermal debinding at different temperature. The debinded samples were sintered at different temperature for 60 min. Mechanical property, microstructural characterization and electrochemical property of the sintered samples were performed using tensile testing, hardness, optical, scanning electron microscopy and electrochemical corrosion experiments. Sintered samples were immersed in a simulated body fluid (SBF) with elemental concentrations that were comparable to those of human blood plasma for a total period of 15 days. Both materials were implanted in fibroblast culture for biocompatibility evaluations were carried out. Results of study showed that sintered 316L and 316L with NiB addition samples exhibited high mechanical and corrosion properties in a physiological environment. Especially, 316L with NiB addition can be used in some bioapplications.

Mechanical Properties of Polymers Filled with Iron Powder

Mechanical properties of metal-polymer matrix composites were investigated experimentally. High density polyethylene (HDPE), polypropylene (PP), and polystyrene (PS) were used as the polymer matrix and Fe powder in 5, 10, and 15 vol% was used as the metal. The modulus of elasticity, yield and tensile strength, % elongation, Izod notched impact strength, Shore D hardness, and fracture surfaces of the composites were determined. It was found that vol% Fe reduced the Izod impact strength of HDPE much more than that of PP and PS, while Fe powder increased the hardness of HDPE more than that of PP and PS. Among the composites, PS-Fe composites had higher yield, tensile strength and modulus of elasticity than HDPE-Fe and PP-Fe composites. However, % elongation of PS-Fe composites was lower than that of the other composites. In addition, HDPE- and PP-based composites exhibited ductile type fracture, while PS-Fe composites exhibited brittle type fracture.

Ni-625 Superalloy Foam Processed by Powder Space-Holder Technique

In this work, porous Ni-625 superalloys were produced by use of a water soluble pore forming agent prior to sintering. Carbamide particles were used as the space-holder materials. After mixing and compaction, the space-holder particles were extracted using warm water leaching over a range of temperatures. The porous green parts were subsequently thermally debinding to remove the paraffin wax under a pure Argon atmosphere, and subsequently sintered at high vacuum. The effects of volume fraction of space-holder particles on density, porosity, and elastic modulus were investigated. Microstructures were captured using optical and scanning electron microscopy. Pore size was quantified using image analysis software integral to the scanning electron microscopy. In addition, compression tests were conducted on the sintered samples.

Physical and Mechanical Properties of Polypropylene Reinforced with Fe Particles

ABSTRACT The physical and mechanical properties of Polypropylene (PP) and Fe-PP polymer composites containing 5, 10, and 15 vol% Fe were investigated experimentally. After preparing PP and Fe–PP polymer composites with a twin screw extruder and injection molding, the following properties were determined: yield and tensile strength, the modulus of elasticity, % elongation, hardness (Shore D), Izod impact strength (notched), melt flow index (MFI), Vicat softening point, Heat deflection temperature (HDT), and melting temperature (Tm) of PP and metal-polymer composites. As compared to PP, It was found that by increasing the vol% of Fe in PP, notched Izod impact strength, yield and tensile strength, and % elongation decreased. On the other hand, the modulus of elasticity, hardness, MFI, vicat softening point, and HDT values increased with the amount of iron.

Sintering and Mechanical Properties of Injection Molded Low Cost Ti Alloys

This study focuses on the injection molding of Ti-Fe alloys. Low cost Ti alloy (Ti-Fe) was manufactured following a powder injection molding route. The Ti and Fe powders were dry mixed and molded with wax based binder. Binder debinding was performed by solvent and thermal method. After dedinding, the samples were sintered at 1100 oC and 1300 oC for 1 h in vacuum. Metallographic studies were conducted to extend densification and the corresponding microstructural changes. The sintered samples were characterized by measuring tensile strength, elongation and hardness. All powder, fracture surfaces of molded and sintered samples were examined using scanning electron microscope. The sintered density, tensile strength and hardness of injection molded Ti-Fe samples increases with increasing sintering temperature.

The Effect of Bronze Particles on the Physical and Mechanical Properties of Acrylonitrile-Butadiene-Styrene Copolymer

In this study, 5, 10, and 15 vol.% of bronze (Cu-10 wt.% Sn) powder on the physical and mechanical properties of Acrylonitrile-Butadiene-Styrene (ABS) were investigated experimentally. After preparing metal-polymer matrix composites (PMC) with a twin screw extruder and injection molding, fracture surface, the modulus of elasticity, yield and tensile strength, percentage elongation, Izod impact strength, hardness (Shore D), melt flow index (MFI), heat deflection temperature (HDT), Vicat softening point, and glass transition temperature (T g) of each sample were determined. As compared to the unfilled ABS. It was found that by increasing the vol.% of bronze in ABS, yield and tensile strength, % elongation, Izod impact strength, MFI values decreased, while the modulus of elasticity, Shore D hardness, Vicat softening point, and HDT values increased.

Experimentation and Analysis of Powder Injection Molded Ti10Nb10Zr Alloy: A Promising Candidate for Electrochemical and Biomedical Application

This paper describes the microstructural, mechanical and corrosion properties of injection molded Ti10Nb10Zr alloys. Ti10Nb10Zr powder was injection molded with wax-based binder. The critical powder loading for injection molding was 55 vol% for feedstock. Binder debinding was performed in solvent and thermal method. After debinding the samples were sintered at different temperatures and times in vacuum atmosphere (10−5 mbar) to obtain fully dense parts. Metallographic studies were conducted to determine the extent of densification and the corresponding microstructural changes. The electrochemical property and biocompatibility of the sintered samples were performed electrochemically, by selfbody-fluid immersion tests and cell culture experiments. The results show that Ti10Nb10Zr alloys could be sintered to a maximum 99% of theoretical density. Maximum ultimate tensile strength, elongation and hardness obtained were 748 MPa, 14.3 and 114 HRB respectively at 1500 C for 3 h. Additionally, the sintered Ti10Nb10Zr alloys exhibited high mechanical and corrosion properties in a physiological environment.