Wyniki wyszukiwania - BazTech

1

Biological evaluation of selective laser melted magnesium alloy powder

Pawlak Andrzej P., Szymczyk-Ziółkowska Patrycja E., Junka Adam, Chlebus Edward

Acta of Bioengineering and Biomechanics

|

2021

|

Vol. 23, no. 1

121--133

EN

Purpose: The current study examined magnesium alloy AZ31B specimens manufactured with Additive Manufacturing method (selective laser melting – SLM) to investigate the applicability of this technology for the production of medical devices. Methods: Osteoblast cells and bacterial biofilm growth ability on specimen was examined and the effect of surface state on corrosion resistance was evaluated by electrochemical and immersion methods. Results: High survival of hFOB cells, as well as a strong tendency for Pseudomonas aeruginosa and Staphylococcus aureus biofilm proliferation on the surface of the tested specimens were shown. SLM-processed AZ31B alloy has a higher corrosion resistance in 0.9% NaCl solution and in a multi-electrolyte saline solution than the material in a conventional form of a rolled sheet. Conclusions: It has been demonstrated that the strong development of the surface of as-built processed specimens results in a significantly increased corrosion rate, which hinders the production of complex structures in tissue engineering products that support cell ingrowth.

2

Comparative study of laser melting and pre‑placed Ni–20% Cr alloying over nodular iron surface

Jeyaprakash N., Yang Che-Hua, Duraiselvam Muthukannan, Sivasankaran S.

Archives of Civil and Mechanical Engineering

|

2020

|

Vol. 20, no. 1

282--293

EN

In this study, two techniques such as laser surface melting (LSM) and laser surface alloying (LSA) were performed to protect the surface layers of nodular cast iron as it is used to manufacture different machine parts like cams, beds, camshafts, crankshafts, cylinders and engine blocks. The main objective of this research work is to examine the effects of LSM and LSA processes on phases, microstructure, hardness, wear resistance and surface roughness. The outcomes of both LSM and LSA specimens show a homogeneous structure, effective bonding of alloy powders with the base metal and crack-free surfaces. The hardness was improved 4 times (LSM) and 2.62 times (LSA) when compared with the base material. The tribological test shows improved wear resistance of LSM (8.82 × 10−7 kN) and LSA (1.32 × 10−6 kN) samples compared to the base material (4.36 × 10−6 kN). The examined wear tracks indicate that mild abrasion, adhesion and delamination were the major wear mechanisms. The reason for the enhancement of wear resistance is the refinement of microstructure, the solid solution strengthening effect and good bonding between alloy powders and base material. The LSM technique is a potential method to improve the tribological properties of industrial materials.

3

Wytwarzanie przyrostowe stopów amorficznych metodą selektywnego stapiania laserowego

Żrodowski Ł., Wysocki B., Błyskun P., Wróblewski R., Kurzydłowski K.J., Święszkowski W.

Mechanik

|

2017

|

R. 90, nr 1

50--51

PL

W artykule opisano proces optymalizacji stapiania proszków szkła metalicznego na bazie żelaza. Stapianie prowadzono przy różnych parametrach mocy lasera i strategiach przyrostowego wytwarzania – tak, aby uzyskać wysoką zawartość fazy amorficznej. Wyniki badań potwierdzają istotny wpływ mieszania jeziorka ciekłego metalu oraz szybkości nagrzewania wierzchniej warstwy materiału na amorfizację.

EN

In the paper optimization process for selective laser melting of Fe-based metallic glass powder has been described. Melting process has been conducted with various laser power and parameters to increase materials amorphisation degree. Results showed strong influence of melt pool mixing and heating rate on amorphisation.

4

Ocena jakości wykonania wybranego elementu z proszków metali metodą laserowego wytwarzania przyrostowego

Mazurkiewicz A., Nędzi B.

Autobusy : technika, eksploatacja, systemy transportowe

|

2016

|

R. 17, nr 12

1204--1211

PL

W artykule oceniono podstawowe parametry wpływające na jakość wyrobu otrzymywanego z proszków metali metodą laserowego wytwarzania przyrostowego. Zwrócono uwagę na wpływ przyjętej technologii wytwarzania na właściwości mechaniczne materiału i związaną z tym niejednorodność struktury skutkującej wadami wyrobu. Przedstawiono zróżnicowaną budowę strukturalną materiału powstałą w różnych obszarach wyrobu. Pokazano wpływ obróbki cieplnej na ujednorodnienie struktury materiału.

EN

The article rated basic parameters affecting the quality of the product obtained from the metal powder by laser additive manufacturing. Attention was paid to the impact of the adopted production technology on the relevant mechanical material-Justice and the related non-uniformity of the structure resulting in defective product. Shown diverse structural building material formed in different regions of the article. Shows the effect of heat treatment on the homogenization of the structure of the material.

5

Structure and properties of surface layer of hot-work tool steels alloyed using high power diode laser

Dobrzański L. A., Jonda E., Labisz K.

Journal of Achievements in Materials and Manufacturing Engineering

|

2009

|

Vol. 37, nr 2

617-621

EN

Purpose: In this paper the results of remelting and alloying laser parameters on the structure and properties of the surface layer of the X40CrMoV5-1 and 32CrMoV12-28 hot work tool steels, using the high power diode laser (HPDL) are presented. Design/methodology/approach: The effect was determined of the main alloying parameters on hardness, abrasive wear resistance and roughness. The hot work tool steels conventionally heat treated were used as reference material and the tantalum carbide was used as an alloying material. The remelted layers which were formed in the surface of investigated hot work tool steels were metallographically examined and analyzed using a hardness testing machine. Findings: It was found out in examinations of the surface layer that it can be possible to obtain high quality top layer with higher hardness and abrasive wear resistance compared to material after conventional heat treatment. Research limitations/implications: The surface layer and its properties are elements which are critical for lifetime of tools and parts of machines and also for lifetime of whole technical equipment. If the working surface of a tool or its part is exposed to rough friction, an intensive mass and volume loss occurs. In this case it is reasonable to produce a surface layer which is extremely wear resistant to avoid the mass and volume loss. Originality/value: The research results of this type of heat treatment show that there is a possibility of applying the worked out technology to manufacturing or regeneration of chosen hot working tools.

6

Laserowe utwardzanie powierzchni tytanu z wykorzystaniem syntezy TiC.

Zimnicki J., Wendler B., Pawlak R.

Inżynieria Materiałowa

|

2000

|

R. XXI, nr 6

490-493

PL

W pracy przedstawiono metodę utwardzania powierzchni tytanu wytwarzając węglik TiC w warstwie wierzchniej metalu. Węglik wytworzono stapiając warstwę wierzchnią tytanu wiązką laserową w obecności wcześniej osadzonej warstwy koloidalnego grafitu. Badania dotyczyły morfologii powierzchni, składu chemicznego i fazowego powstałych przetopów oraz ich mikrostruktury i mikrotwardości. Morfologia powierzchni po obróbce laserowej była różna w zależności od użytej gęstości mocy wiązki oraz stopnia nakładania się sąsiednich przetopów. Częściowo zachodzące na siebie lokalne przetopy tworzyły ścieżki, w których stwierdzono metodą rentgenograficzną obecność krystalitów faz alfa-Ti oraz delta-TiC. Twardą fazę węglikową o wyraźnej strukturze dendrytycznej obserwowano w całym przetopie. Kierunki dendrytów w pobliżu powierzchni są do niej prostopadłe, co wynika z nierównowagowej, szybkiej krystalizacji fazy delta-TiC w warunkach występującego jednokierunkowego gradientu temperatury. Ilość fazy węglikowej zależała od gęstości mocy promieniowania oraz stopnia nakładania sąsiednich ścieżek i lokalnych przetopów. Na zgładach poprzecznych oprócz tytanu i węgla stwierdzono również obecność tlenu. Mikrotwardości zmierzone na przekrojach poprzecznych zawierały się w granicach 150 HV0.01-1000 HV0.01. Rozkłady mikrotwardości charakteryzują się dużą niejednorodnością, która wynika z intensywnego mieszania i szybkiego stygnięcia cieczy.

EN

A method of titanium surface hardening is presented in the paper in which a hard carbide delta-TiC phase is being created in the vicinity of the titanium surface. The creation of the carbide phase is due to laser melting of the titanium surface previously coated with a thin layer of a colloidal graphite. The experimental conditions as well as the parameters of the pulse laser beam are given. The morphology of the laser treated titanium surface, chemical and phase composition of the melted zone beneath the titanium surface as well as the microstructure and microhardness of the zone have been analysed. The titanium surface after laser treatment has been observed with use of optical microscopy. Surface morphology was changing with power density of the laser beam and with superposition of the adjacent melted zones. The zones were forming long path in which two phases alpha-Ti and delta-TiC have been disclosed by means of X-ray diffractometry. The chemical composition of the melted zones has been performed on the cross sections by means of the electron probe microanalysis. The zones were composed mostly of titanium and carbon atoms, however some amounts of oxygen from the surrounding atmosphere has been detected as well. The hard carbide phase with a dendritic morphology has been observed in far and wide of the melted zones. The directions of the dendrites' axes in the vicinity of the titanium surface are nearly perpendicular to the surface. That phenomenon is due to the solidification of the molten pool under the circumstances of an unidirectional thermal gradient created in result of the laser treatment of the surface. The volume fraction of the carbide phase in the melted zone was changing depending on the superposition of the adjacent zones or paths. The microhardness on the cross sections was changing very irregularly. Its values measured on the section along two straight lines perpendicular to the titanium surface are given. That irregularity is due to a rather intensive stirring in the molten pool succeeded by a very rapid solidification.