Odporność korozyjna oraz mikrostruktura stali AISI 316L po odkształceniu plastycznym na zimno

In the paper, results of microstructure and hardness examination of cold-worked alloyed steel AISI 316L are presented. In addition, determined was corrosion resistance of the steel in the Ringer solution. Corrosion tests were performed after cold working with 10, 20, 30, 40 and 50% ratio. Potentiodynamic tests included recording polarisation curves as well as determining corrosive potential and corrosive current for various cold working ratios. Cross-sections of the specimens after corrosion tests were observed and analysed using a scanning microscope.W artykule przedstawiono wyniki badań mikrostruktury oraz twardości stali stopowej AISI 316L odkształconej plastycznie. Przeprowadzono również badania odporności korozyjnej tej stali wyznaczone w roztworze Ringera. Badania przeprowadzono w celu określenia zmian odporności korozyjnej stali, poddanej kształtowaniu plastycznemu na zimno, po uzyskaniu zgniotów 10, 20, 30, 40 oraz 50%. Zakres badań potencjodynamicznych obejmował: rejestrację krzywych polaryzacyjnych, określenie wartości potencjału korozyjnego i prądu korozyjnego przy różnych stopniach zgniotu. Po przeprowadzonych badaniach korozyjnych dokonano obserwacji powierzchni próbek za pomocą mikroskopu skaningowego w celu zarejestrowania powstałych zmian

Grain size reduction in the 713C nickel superalloy as a result of heat treatment

The paper presents metallographic test results for the 713C nickel superalloy after heat treatment and crystallographic orientation analysis performed with the EBSD method. The 713C alloy was subjected to annealing in the temperature of 950 ºC for 30 hours followed by aircooling. As a result of the applied heat treatment the local grain size reduction in the alloy was observed. It has been found that in the primary grains the new subgrains of different crystallographic orientation are created. Between the new grains and the primary grains the boundaries of high angle appear. Orientation change in the micro-areas is closely related to the carbides rebuilding and volume diffusion of elements dissolved in the γ - γ’ alloy matrix and the (NbTi)C carbides

Characteristics of pit in AlSl 316L steel after testing in various corrosive solutions

Badania miały na celu rejestrację zmian zachodzących w strukturze austenitycznej stali AlSl 316L po badaniach potencjodynamicznych, w różnych roztworach korozyjnych. Roztwory korozyjne różniły się pod względem zawartości jonów Cl-. Zastosowano roztwór korozyjny 3% NaCl i roztwór symulujący płyny fizjologiczne w organizmie ludzkim. Badania przeprowadzono z zastosowaniem metod skaningowej mikroskopii elektronowej SEM i mikroanalizatora promieniowania rentgenowskiego EDX.Microscopic examination on austenitic steel AlSl 316L after potentiodynamic tests in various corrosive solutions, were performed using an electron scanning microscope JEOL JSM-5800LV, to record the occurred corrosion changes (surface and pit microstructure). For corrosion testing, two reagents were used: 3% water solution of sodium chloride and Ringer’s solution enriched in sodium chloride and hexahydrated calcium chloride. Selection of the corrosive medium was related to application of the examined steel for medical implants and was aimed at simulating the environment of physiological fluids

Characteristic of intermetallic phases in cast dental CoCrMo alloy

Abstract Apart from chromium and molybdenum, casting alloys of cobalt usually contain also up to 0.35 % of carbon. With significant content of carbon, presence of carbide-forming alloying elements results in creating carbide phases. These alloys are characterised by dendritic structure of solid solution of chromium and molybdenum in cobalt with interdendritically precipitated carbides. Because of high chromium content, dominating are M23C6-type carbides, but chromium-rich carbides can be also of M7C3 and M3C2-types. The other elements in the alloy result in creating M6C and MC-type carbides. In the case of low carbon content, creating carbides and forming intermetallic phases based on the alloying elements and cobalt become limited. The presented research was aimed at characterising structure of the cobalt-based dental alloy containing trace quantity of carbon. Characterised were intermetallic phases hardening the alloy. Microscopic examinations using light microscopy, SEM and TEM were carried out. Chemical microanalysis of the precipitates using X-ray analyser EDS was performed, as well as phase analysis using selected area electron diffraction