Piotr Budzyński

Method for Testing and Evaluating Grassy Runway Surface

The main purpose of this study is to develop a test method to evaluate grassy airfields by determining the mechanical properties that affect airfield performance during takeoff, touchdown, and landing roll. A number of airfields with grassy or partially grassy runways in European Union countries could be more effective for flight operations with better knowledge of the surfaces and their impact on field performance. The proposed method could provide this information. The concept of the method (and an advantage over the existing methods) is to determine 1)xa0wheel–surface braking friction, 2)xa0rolling resistance, and 3)xa0surface roughness. All these parameters are essential for wheel–soil interactions and performance of an airplane on the airfield. Friction coefficients would be determined with a portable tester, which has been designed and built. The complete test method will also include procedures, instructions, and comparison charts. The plan is to present the complete test method for certification so it m...

Long-range effect of ion implantation of Raex and Hardox steels

Ion implantation involves introduction of ionized atoms of any element (nitrogen) to metals thanks to the high kinetic energy that they acquired in the electric field. The distribution of nitrogen ions implanted at E = 65 keV energy and D = 1.1017 N+ /cm2 fluence in the steel sample and vacancies produced by them was calculated using the SRIM program. This result was confirmed by RBS measurements. The initial maximum range of the implanted nitrogen ions is ~0.17 μm. This value is relatively small compared to the influence of nitriding on the thickness surface layer of modified steel piston rings. Measurements of the friction coefficient during the pin-on-disc tribological test were performed under dry friction conditions. The friction coefficient of the implanted sample increased to values characteristic of an unimplanted sample after ca. 1500 measurement cycles. The depth of wear trace is ca. 2.4 μm. This implies that the thickness of the layer modified by the implantation process is ~2.4 μm and exceeds the initial range of the implanted ions by an order of magnitude. This effect, referred to as a long-range implantation effect, is caused by migration of vacancies and nitrogen atoms into the sample. This phenomenon makes ion implantation a legitimate process of modification of the surface layer in order to enhance the tribological properties of critical components of internal combustion engines such as steel piston rings.

The influence of nitrogen ion implantation on microhardness of the Stellite 6 alloy

Cobalt alloys known as Stellite used to produce or surfacing machine elements subjected to combustion gases and heat. They are used a currently in the manufacture of valves and valve seats in internal combustion engines. Because of the small thermal conductivity, stellite may not be subjected heat treatment. In order to improve the mechanical properties of cobalt alloys, samples were implanted with nitrogen ions with 65 keV energy and ion dose of 11016, 51016, 11017 N+/cm2. The influence of ion implantation on properties of strength was determined by measuring microhardness using a Vickers hardness test. The measurement results allowed to determine the increase in the microhardness of 20% with dose 51016 N+/cm2 compared to the sample not implanted. Implantation of nitrogen ions can increase the strength of the valves and the valve seats having Stellite without changing the external dimensions of the final element, and without interfering with its inner structure by low-temperature of modification the surface layer.

Surface morphology and phase stability of titanium irradiated with 168 MeV 136Xe ions

Abstract A titanium sample was irradiated with Xe 168 MeV energy at fluences of 1 × 1014, 2.2 × 1014, and 5 × 1014 ions · m−2. Changes induced by the ions with irradiation were analysed with an atomic force microscope, scanning electron microscope, and X-ray diffractometer. The irradiation at a fluence of 1 × 1014 ions · cm−2 leads to formation of hillocks with a density of 9 × 106 hillocks · cm−2. An increase in the fluence value results in disappearance of the hillocks and formation of void–dislocation lines. The changes in the surface topography are accompanied by a change in the relative content of the hcp (α) and fcc phases. The substantial changes in the crystalline structure (increased content of the fcc phase, reduction of lattice constants, changes in stresses) resulted from irradiation at a fluence of 1 × 1014 ions · cm−2. Irradiation of massive titanium samples with xenon ions at a fluence of 168 MeV 1 × 1014 ions · cm−2 at room temperature leads to a transition of ∼10% of the hexagonally closed-packed phase – hcp (α) into a face centred cubic structure (the fcc phase). Higher Xe ion fluences contribute to further reduction of lattice constants and crystallite sizes as well as reduction of the phase fcc content and lower values of stresses. It has been found for the first time that irradiation at higher fluences leads to partial recovery of the hcp (α) phase. Irradiation changes the texture of∼50% of the fcc phase crystallites.

Tribological Properties of Stellite 6 Cobalt Alloy Implanted with Nitrogen Ions Determined in the Tests Conducted in Engine Fuel Atmosphere

The influence of nitrogen ion implantation on the tribological properties of Stellite 6 cobalt alloy was investigated. The tribological tests were conducted using a pin / ball on disc in the atmosphere of engine fuels. In the study, cobalt alloy was implanted with 60 keV nitrogen ions at the fluence of 1∙1016 and 5∙1016 N+/cm2. The wear trace was measured using the Form Talysurf Intra Taylor Hobson profilometer. The results demonstrate that nitrogen ion implantation affects the friction coefficient and wear. The effect of nitrogen ion implantation depends on the environment in which the tribological test is carried out, the sample temperature and the presence of friction products in the friction node.

Microstructure and electrical conductivity of titanium irradiated with swift heavy ions

Radiation damage caused by heavy ions may induce changes in the surface topography, crystalline structure, and electrical conductivity of irradiated materials. Titanium was irradiated with 130 MeV xenon ions and 260 MeV krypton ions at a fluence of 1, 3, and 5×10 ions/cm. The irradiation altered the surface topography of the sample, caused transformation of the α phase into the fcc phase, and reduced electrical conductivity with the increasing irradiation fluence. Streszczenie. Uszkodzenia radiacyjne wywołane ciężkimi jonami mogą powodować zmiany topografii powierzchni oraz zmiany w strukturze krystalicznej i przewodności elektrycznej napromieniowanych materiałów. Tytan napromieniowano jonami Xe o energii 130 MeV i jonami kryptonu o energii 260 MeV. Doza napromieniowanych jonów była równa 1, 3 i 5×10 jonów/cm. Napromieniowanie zmienia: topografię powierzchni próbki, powoduje transformacje fazy α w fazę fcc oraz obniża przewodność elektryczną wraz ze wzrostem dozy napromieniowania. (Mikrostruktura oraz przewodność elektryczna tytanu po napromieniowaniu jonami wysokoenergetycznymi).

A portable wheel tester for tyre-road friction and rolling resistance determination

The paper describes theory of operation, design and construction as well as results from primarily experiments with a portable wheel tester that has been developed by the authors as a device for on-site determination of tyre-road braking/driving friction and rolling resistance. The paper includes schematics, drawings, descriptions as well as graphical results form early tests with the presented device. It is expected that the tester can be useful in road accident reconstruction applications as well as in vehicle dynamics research.