Papers by Author: Waldemar Serbiński

Abstract: The main objective of here presented research is a design the scaffold/porous titanium (Ti) alloy based composite material demonstrating better biocompatibility, longer lifetime and bioactivity behaviour for load-bearing implants. The development of such material is proposed by making a number of consecutive tasks. Modelling the mechanical, biomechanical and biological behavior of porous titanium structure and an elaboration of results is performed by mathematical methods, including FEM and fuzzy logic. The development of selected Ti-13Zr-Nb alloy with designed porosity and no harmful effects is made by powder metallurgy (PM) with and without space holders, and by rapid prototyping with an use of selective laser melting (SLM). The development of an oxidation technology resulting in high corrosion resistance and bioactivity is carried out by electrochemical oxidation, gaseous oxidation and chemical oxidation, and their combination. The HA depositon is made by electrochemical and chemical (alternate immersion) methods. The core material is designed as a combination of natural polymer and bioceramics in order to allow slow dissolution followed by stepwise growth of bone tissue and angiogenesis, preventing local inflammation processes, and sustaining the mechanical strength close to that of non-porous material.

Abstract: The titanium and its alloys can be subjected to surface treatment, including laser treatment. In this work a new laser treatment at cryogenic conditions of Ti6Al4V alloy has been described. The work has been aimed at establishing whether such surface treatment could be suitable for implants working under wear in biological corrosive environment. The remelting has been made with the use of CO₂ continuous work laser at laser power between 3 and 6 kW, at scan rate 0.5 and 1 m/s. The microstructure, surface topography, hardness, microhardness and wear linear rate and mass loss under tribological tests made in Ringer`s solution have been made. The results have shown that despite the surface cracking the tribological properties in simulated body fluid have been substantially improved.

Abstract: Research on improvement of structure and fabrication methods of the bone implants are carried out for many years. Research are aimed to shape the structures, that will have a Young's modulus value similar to the value of the human bones Young's modulus. Depending on the porosity, Young’s moduli can even be tailored to match the modulus of bone closer than solid metals can, thus reducing the problems associated with stress shielding of a human bones. The designed structure should also be characterized by a high abrasion and corrosion resistance to and allow bone ingrowth in the implant material to make the best bone-implant fixation. For this purpose, implants should have a porous structure with an appropriate pore size and with open-cell porosity. Material for bone implants must also have a high biocompatibility and bioactivity. Following these requirements, the metallic porous materials appear to be the most suitable material for bone implants. In this paper a various methods of a porous materials fabrication for bone implants are listed. It was shown that titanium and its alloys (e.g. Ti6Al4V or Ti13Nb13Zr) are widely used as biomaterials for implants. Research in order to increase their wear and corrosion resistance and to improve their biocompatibility and bioactivity are still carried out. One of the most effective methods of manufacturing the porous materials is a powder metallurgy (PM). In this paper the results of research under shaping the structure of the porous titanium alloy Ti13Nb13Zr are also presented. As a manufacturing method of the porous material from the investigated and mentioned above Ti alloy, the powder metallurgy (PM) was choosen - with and without the use of a space holders. Method of fabrication a spherical powder from the aforementioned Ti alloy and results of its morphology research are discussed. The applied powder compaction method (with use and without use of space holders) and the influence of a sintering process on the final microstructure morphology of porous material obtained from Ti13Nb13Zr alloy are also presented and discussed.

Abstract: Aluminium alloys are the materials of choice when high-strenght-to-weight rations are required in structural components, and used widely in the automotive and aerospace industries. As an example, the use of an aluminium components in the automobile industry has greatly increased due to weight savings and resultant fuel economy improvements. There are many methods of surface consolidation of an aluminium alloys. This work presents the hybrid creation method of the newly layers type (Mn-P) on the AlSi13Mg1CuNi alloy, its microstructure, hardness, chemical and phase compositions as well as wear and corrosion resistance. Growth the wear resistance of an aluminium alloy coated with the layer type (Mn-P) is visable. The corrosion characteristics of these layers are also considered.

Abstract: The purpose of this paper is to show results of laser treatment at cryogenic conditions of the SUPERSTON alloy used for ship’s propellers. That modification process ought to bring beneficial changes of microstructure and residual stresses in the surface layer. During the laser remelting at cryogenic conditions the microstructure changes significantly. This is related to synergistic effects of the solidification rate, phase transformations in the solid state and laser treatment parameters. That crystallization process had influence on functional properties such as corrosion and cavitation resistance of the SUPERSTON alloy which were tested during researches.

Abstract: The main reason of the surface modification of the components such as pistons and cylinder blocks made of cast aluminium alloys is to obtain high hardness, wear and corrosion resistance of the working surface for larger lifetime of the motor-car and aircraft engines. In that aspect, the new conception of development – by hybrid method – of surface layers containing manganese, nitrogen, sulphur (Mn-N-S) and manganese, nitrogen, oxygen (Mn-N-O) on aluminium alloys was considered in this paper. These layers are diffusively connected with aluminium base, possess high hardness and good tribological properties. The aim of this paper is to present the influence of the proposed consolidation method on microstructure, phase composition, microhardness, wear and corrosion characteristics of the surface layers produced on AlSi13Mg1CuNi alloy.

Abstract: The purpose of this paper is to demonstrate the method of laser remelting at cryogenic conditions of the SUPERSTON alloy and its influence on microstructure and cavitation wearing. The cavitation test was performed using the rotating disc facility in IPM PAN Gdansk. During the cavitation test, the mass loss of the material with different parameters of laser remelting was determined. Surface and cross-section microstructure of the SUPERSTON alloy after laser treatment and cavitation test were observed by scanning electron microscope. The cavitation resistance of the remelted SUPERSTON alloy was approximately 40% higher in comparison to the base material.