Papers by Bartłomiej A Wysocki
The aim of this study was to fabricate by selective laser melting hybrid solid-porous titanium sc... more The aim of this study was to fabricate by selective laser melting hybrid solid-porous titanium scaffolds with regions of different porosities (500, 700 and 900 µm) controlled by the size of the diamond structure. In order to remove unmelted powder particles, obtain the required surface finish and render CAD model dimensions fabricated structures were chemically polished in a mixture of HF/HNO3 acids. The obtained results show that SLM combined with chemical post-processing is a perspective tool for fabrication of the hybrid titanium structures with properties which allows to mimics human bone to a greater extent than solutions utilized nowadays.
A new powder production method has been developed to speed up the search for novel alloys for add... more A new powder production method has been developed to speed up the search for novel alloys for additive manufacturing. The technique involves an ultrasonically agitated cold crucible installed at the top of a 20 kHz ultrasonic sonotrode. The material is melted with an electric arc and undergoes pulverization with standing wave vibrations. Several different alloys in various forms, including noble and metallic glass alloys, were chosen to test the process. The atomized particles showed exceptional sphericity, while powder output suitable for additive manufacturing reached up to 60%. The AMZ4 metallic glass powder remained amorphous below the 50 μm fraction, while tungsten addition led to crystallization in each fraction. Minor contamination and high Mn and Zn evaporation, especially in the finest particles, was observed in atomized powders. The innovative ultrasonic atomization method appears as a promising tool for material scientists to develop powders with tailored chemical composi...
Antibiotics
Dental implants are, nowadays, established surgical devices for the restoration of lost teeth. Co... more Dental implants are, nowadays, established surgical devices for the restoration of lost teeth. Considered as an alternative for traditional prosthetic appliances, dental implants surpass them in reliability and patient feedback. Local drug delivery around the implants promotes osseointegration and reduces peri-implantitis. However, there are currently no methods of a multiple, precise topical administration of drugs to the implant area. Engineering coatings on the implants, drug application on carriers during implantation, or gingival pockets do not meet all requirements of dental surgeons. Therefore, there is a need to create porous implants and other medical devices that will allow a multiple drug delivery at a controlled dose and release profile without traumatic treatment. Due to the growing demand for the use of biologically active agents to support dental implant treatment at its various stages (implant placement, long-term use of dental superstructures, treatment of the peri-...
International Journal of Molecular Sciences
In this work, NiTi alloy parts were fabricated using laser powder bed fusion (LBPF) from pre-allo... more In this work, NiTi alloy parts were fabricated using laser powder bed fusion (LBPF) from pre-alloyed NiTi powder and in situ alloyed pure Ni and Ti powders. Comparative research on the corrosive and biological properties of both studied materials was performed. Electrochemical corrosion tests were carried out in phosphate buffered saline at 37 °C, and the degradation rate of the materials was described based on Ni ion release measurements. Cytotoxicity, bacterial growth, and adhesion to the surface of the fabricated coupons were evaluated using L929 cells and spherical Escherichia coli (E. coli) bacteria, respectively. The in situ alloyed NiTi parts exhibit slightly lower corrosion resistance in phosphate buffered saline solution than pre-alloyed NiTi. Moreover, the passive layer formed on in situ alloyed NiTi is weaker than the one formed on the NiTi fabricated from pre-alloyed NiTi powder. Furthermore, in situ alloyed NiTi and NiTi made from pre-alloyed powders have comparable cyt...
Materials
Selective Laser Melting (SLM) is a manufacturing technique that is currently used for the product... more Selective Laser Melting (SLM) is a manufacturing technique that is currently used for the production of functional parts that are difficult to form by the traditional methods such as casting or CNC (Computer Numerical Control) cutting from a wide range of metallic materials. In our study, a mixture of commercially pure titanium (Ti) and 15% at. aluminum nitride (AlN) was Selective Laser Melted to form three-dimensional objects. The obtained 4 mm edge cubes with an energy density that varied from 70 to 140 J/mm3 were examined in terms of their microstructure, chemical and phase composition, porosity, and Vickers microhardness. Scanning Electron Microscopy (SEM) observations of the etched samples showed inhomogeneities in the form of pores and unmelted and partly melted AlN particles in the fine-grained dendritic matrix, which is typical for titanium nitrides and titanium aluminum nitrides. The AlN particles remained unmelted in samples, but no porosity was observed in the interface a...
New approach to amorphization of alloys with low glass forming ability via selective laser melting
Journal of Alloys and Compounds
The influence of chemical polishing of titanium scaffolds on their mechanical strength and in-vitro cell response
Materials Science and Engineering: C
International Journal of Molecular Sciences
The use of laser 3D printers is very perspective in the fabrication of solid and porous implants ... more The use of laser 3D printers is very perspective in the fabrication of solid and porous implants made of various polymers, metals, and its alloys. The Selective Laser Melting (SLM) process, in which consolidated powders are fully melted on each layer, gives the possibility of fabrication personalized implants based on the Computer Aid Design (CAD) model. During SLM fabrication on a 3D printer, depending on the system applied, there is a possibility for setting the amount of energy density (J/mm 3) transferred to the consolidated powders, thus controlling its porosity, contact angle and roughness. In this study, we have controlled energy density in a range 8-45 J/mm 3 delivered to titanium powder by setting various levels of laser power (25-45 W), exposure time (20-80 µs) and distance between exposure points (20-60 µm). The growing energy density within studied range increased from 63 to 90% and decreased from 31 to 13 µm samples density and Ra parameter, respectively. The surface energy 55-466 mN/m was achieved with contact angles in range 72-128 • and 53-105 • for water and formamide, respectively. The human mesenchymal stem cells (hMSCs) adhesion after 4 h decreased with increasing energy density delivered during processing within each parameter group. The differences in cells proliferation were clearly seen after a 7-day incubation. We have observed that proliferation was decreasing with increasing density of energy delivered to the samples. This phenomenon was explained by chemical composition of oxide layers affecting surface energy and internal stresses. We have noticed that TiO 2 , which is the main oxide of raw titanium powder, disintegrated during selective laser melting process and oxygen was transferred into metallic titanium. The typical for 3D printed parts post-processing methods such as chemical polishing in hydrofluoric (HF) or hydrofluoric/nitric (HF/HNO 3) acid solutions and thermal treatments were used to restore surface chemistry of raw powders and improve surface.
Investigation of the relationship between morphology and permeability for open-cell foams using virtual materials testing
Materials & Design
Applied Sciences
Featured Application: This work is a detailed comparison of the direct laser and electron additiv... more Featured Application: This work is a detailed comparison of the direct laser and electron additive manufacturing methods, which could help scientific research institutes and companies choose the best 3D printer system for the fabrication of titanium implants.
Mechanik
Laser Engineering Net Shaping (LENS), which is one of the 3DP techniques, allows for both, the fa... more Laser Engineering Net Shaping (LENS), which is one of the 3DP techniques, allows for both, the fabrication and the modification of surface layer of the product previously prepared. In the current work, using LENS technique, highly developed bioactive layers, were prepared on the surface of the hip prosthesis. Both, fabricated layers and hip prosthesis, were fabricated from Ti-6Al-4V alloy. The tests were carried out using Simulated Body Fluid (SBF) solution, having all the necessary components on the inorganic human blood plasma. Scanning Electron Microscopy (SEM) showed the nucleation of calcium phosphates even after 2 days of immersion. Based on the results obtained in SEM and EDX tests, it can be claimed that Ti-6Al-4V layers manufactured using LENS technique exhibit high bioactivity in in-vitro, in the SBF solution.
Materials, 2016
Nowadays, post-surgical or post-accidental bone loss can be substituted by custom-made scaffolds ... more Nowadays, post-surgical or post-accidental bone loss can be substituted by custom-made scaffolds fabricated by additive manufacturing (AM) methods from metallic powders. However, the partially melted powder particles must be removed in a post-process chemical treatment. The aim of this study was to investigate the effect of the chemical polishing with various acid baths on novel scaffolds' morphology, porosity and mechanical properties. In the first stage, Magics software (Materialise NV, Leuven, Belgium) was used to design a porous scaffolds with pore size equal to (A) 200 µm, (B) 500 µm and (C) 200 + 500 µm, and diamond cell structure. The scaffolds were fabricated from commercially pure titanium powder (CP Ti) using a SLM50 3D printing machine (Realizer GmbH, Borchen, Germany). The selective laser melting (SLM) process was optimized and the laser beam energy density in range of 91-151 J/mm 3 was applied to receive 3D structures with fully dense struts. To remove not fully melted titanium particles the scaffolds were chemically polished using various HF and HF-HNO 3 acid solutions. Based on scaffolds mass loss and scanning electron (SEM) observations, baths which provided most uniform surface cleaning were proposed for each porosity. The pore and strut size after chemical treatments was calculated based on the micro-computed tomography (µ-CT) and SEM images. The mechanical tests showed that the treated scaffolds had Young's modulus close to that of compact bone. Additionally, the effect of pore size of chemically polished scaffolds on cell retention, proliferation and differentiation was studied using human mesenchymal stem cells. Small pores yielded higher cell retention within the scaffolds, which then affected their growth. This shows that in vitro cell performance can be controlled to certain extent by varying pore sizes.
The influence of pore size variation on the pressure drop in open-cell foams
Materials & Design, 2015
Microstructure and mechanical properties investigation of CP titanium processed by selective laser melting (SLM)
Journal of Materials Processing Technology, 2017
Microstructure and mechanical properties investigation of CP titanium processed by selective laser melting (SLM)
Journal of Materials Processing Technology, 2017
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Papers by Bartłomiej A Wysocki