Wyniki wyszukiwania - BazTech

1

The Effect of Re Content on Microstructure and Creep Resistance of Single Crystal Castings Made of Nickel-Based Superalloys

Gancarczyk Kamil, Albrecht Robert, Kawalec Małgorzata, Kościelniak Barbara, Gradzik Andrzej, Szeliga Dariusz, Kawalec Andrzej, Ziaja Waldemar, Motyka Maciej

Advances in Science and Technology. Research Journal

|

2024

|

Vol. 18, no 1

291--305

EN

In this work the effect of crystal structure perfection on the creep resistance of single crystal superalloys. The CMSX-4 and CMSX-4®Plus with increased Re content is analyzed. Single crystal rods are made by directional solidification process at the withdrawal rates 3 and 5 mm/min. The evaluation of microstructure and crystal structure perfection are carried out by light microscopy and X-ray diffraction Ω-scan methods. Creep tests are performed according to ASTM E-139-11 standard at the temperature of 982°C. Mathematical models for the creep resistance of the models are developed for both investigated superalloys. The influence of the crystal structure on the the investigated superalloys are built and the steady state creep rates are determined. Creep strength of both superalloys are compared. The results show that the CMSX-4®Plus nickel superalloy exhibits nearly two times higher creep resistance compared to the conventional CMSX-4 one.

2

Influence of Surface Roughness on the High Temperature / High Strain Low Cycle Fatigue Behavior of Nickel-Based Superalloy Rene®80

Barjesteh Mohammad Mehdi

Archives of Metallurgy and Materials

|

2023

|

Vol. 68, iss. 2

507--516

EN

Since fatigue cracks nucleate and initiate generally at the surface of the rotary components such as blades and discs, the surface condition is the most important factor affecting the fatigue life. Surface scratches are suitable sites for stress concentrations and therefore the nucleation stage of fatigue cracks will be shortened. In the present work, the influence of surface roughness on the low cycle fatigue life behavior of nickel-based superalloy Rene®80 at the temperature of 900°C was evaluated. Results of low cycle fatigue tests (LCF) under strain-controlled condition at 900°C for R = εmin/εmax = 0 and strain rate of 2×10-3 s-1, at a total strain range of 1.2% showed an inverse relationship between fatigue strength and surface roughness of the specimens. In this study, increasing the surface roughness of Rene®80 from 0.2 μm to 5.4 μm led to the decline in the final LCF life from 127 cycles to 53 cycles which indicated a 58.3% reduction in fatigue life at the same condition. Fractography evaluation also exhibited that fatigue cracks initiated from the notch in the rough specimens, whereas in the smooth specimen fatigue cracks nucleated from the internal imperfections and carbides.

3

Evolution of δ phase precipitates in Inconel 625 superalloy additively manufactured by laser powder bed fusion and its modeling with fuzzy logic

Staroń Sylwia, Macioł Piotr, Dubiel Beata, Gola Kewin, Falkus Jan

Archives of Civil and Mechanical Engineering

|

2023

|

Vol. 23, no. 2

art. no. e86, 2023

EN

Experimental and modeling studies of the evolution of plate-like δ phase precipitates in Inconel 625 superalloy additively manufactured by the laser powder bed fusion process are performed. The maximum Feret diameter and the number of particles per unit area are used as parameters describing the size and distribution of the δ phase precipitates. On the basis of microstructural analysis and quantitative image analysis, the effect of time and temperature on the development of δ phase precipitates is determined. The distinct differences in the intensity of precipitation, growth, and coarsening of the δ phase precipitates during annealing at temperatures of 700 and 800 °C up to 2000 h are shown. The experimental results are compared with computational data obtained by thermodynamic modeling. Using the experimentally determined parameters of the δ phase precipitates in different variants of annealing, a fuzzy logic-based phase distribution model is designed. Since the quantity of available data was too small to train a model with the machine learning approach, expert knowledge is used to design the rules, while numerical data are used for its validation. Designed rules, as well as reasoning methodology are described. The proposed model is validated by comparing it with the experimental results. It can be used to predict the size and number density of the δ phase precipitates in the additively manufactured Inconel 625, subjected to long-term annealing at temperatures of 700-800 °C. Due to limited experimental data, the quality of assurance is not perfect, but warrants preliminary research.

4

Incoloy 800HT iron-based superalloy - preliminary characterisation

Purzyńska Hanna, Golański Grzegorz

Journal of Metallic Materials

|

2022

|

Vol. 74, no. 3-4

42--46

EN

The article presents and characterises Incoloy 800HT ironbased superalloy in terms of: chemical composition, heat treatment, microstructure and properties, in its delivery condition. This material is commonly used in process lines in the petrochemical industry, e.g. into components called „pigtails”.

PL

W pracy przedstawiono i scharakteryzowano pod względem: składu chemicznego, obróbki cieplnej, mikrostruktury i właściwości w stanie dostawy nadstop na bazie żelaza Incoloy 800HT. Materiał ten jest powszechnie stosowany w liniach technologicznych w przemyśle petrochemicznym m.in. na elementy zwane pigtails.

5

Wear and surface characteristics on tool performance with CVD coating of Al2O3/TiCN inserts during machining of Inconel 718 alloys

Agari Shailesh Rao

Archive of Mechanical Engineering

|

2022

|

LXIX, nr 1

59--75

EN

The Inconel 718 alloys, which are primarily temperature resistant, are widely used in aviation, aerospace and nuclear industries. The study on dry cutting processes for this alloy becomes difficult due to its high hardness and low thermal conductivity, wherein, most of the heat transfers due to friction are accumulated over the tool surface. Further, several challenges like increased cutting force, developing high temperature and rapid tool wear are observed during its machining process. To overcome these, the coated tool inserts are used for machining the superalloys. In the present work, the cemented carbide tool is coated with chemical vapor deposition multi-layering Al 2O 3/TiCN under the dry cutting environment. The machining processes are carried out with varying cutting speeds: 65, 81, 95, and 106 m/min, feed rate 0.1 mm/rev, and depth of cut 0.2 mm. The variation in the cutting speeds can attain high temperatures, which may activate built-up-edge development which leads to extensive tool wear. In this context, the detailed chip morphology and its detailed analysis are carried out initially to understand the machining performance. Simultaneously, the surface roughness of the machined surface is studied for a clear understanding of the machining process. The potential tool wear mechanism in terms of abrasion, adhesion, tool chip off, delaminating of coating, flank wear, and crater wear is extensively identified during the processes. From the results, it is observed that the machining process at 81 m/min corresponds to a better machining process in terms of lesser cutting force, lower cutting temperature, better surface finish, and reduced tool wear than the other machining processes.

6

Effects of Adding Niobium and Vanadium to Fe-Based Oxide Dispersion Strengthened Alloy

Park Chun Woong, Choi Won June, Byun Jong Min, Kim Young Do

Archives of Metallurgy and Materials

|

2020

|

Vol. 65, iss. 4

1265--1268

EN

In this study, the effects of adding niobium and vanadium to Fe-based oxide dispersion strengthened alloys are confirmed. The composition of alloys are Fe-20Cr-1Al-0.5Ti-0.5Y2 O3 and Fe-20Cr-1Al-0.5Ti-0.3V-0.2Nb-0.5Y2 O3. The alloy powders are manufactured by using a planetary mill, and these powders are molded by using a magnetic pulsed compaction. Thereafter, the powders are sintered in a tube furnace to obtain sintered specimens. The added elements exist in the form of a solid solution in the Fe matrix and suppress the grain growth. These results are confirmed via X-ray diffraction and scanning electron microscopy analyses of the phase and microstructure of alloys. In addition, it was confirmed that the addition of elements, improved the hardness property of Fe-based oxide dispersion strengthened alloys.

7

Rola mikrostruktury w ocenie wrażliwości do pęknięć likwacyjnych polikrystalicznego nadstopu niklu

Rakoczy Ł., Zielińska-Lipiec A.

Hutnik, Wiadomości Hutnicze

|

2018

|

Vol. 85, nr 4

125--132

PL

W niniejszej pracy przeprowadzono charakterystykę składników mikrostrukturalnych w nadstopie na osnowie niklu oraz ich rolę w kontekście wrażliwości wybranego nadstopu do pęknięć likwacyjnych po spawaniu łukowym elektrodą nietopliwą. Materiał dostarczony w postaci odlewu charakteryzował się znaczną niejednorodnością, związaną z różną zawartością pierwiastków w rdzeniach dendrytów i w przestrzeniach międzydendrytycznych. W trakcie obserwacji za pomocą skaningowej mikroskopii elektronowej zaobserowano stosunkowo duży udział wydzieleń fazy międzymetalicznej γ’ w rdzeniach dendrytów. W przestrzeniach międzydendrytycznych, w wyniku segregacji pierwiastków stopowych, w trakcie krzepnięcia odlewu wydzieliły się wyspy eutektyczne γ/γ’, jak również węgliki bogate w pierwiastki trudnotopliwe, mianowicie Hf i Ta. Ciepło wprowadzone do materiału w trakcie spawania doprowadziło w strefie wpływu ciepła do częściowego rozpuszczenia wydzieleń fazy γ’ w osnowie γ. Tworząca się w wysokiej temperaturze cienka nierównowagowa warstewka cieczy zaobserwowana lokalnie wzdłuż granic dendrytów była czynnikiem sprzyjającym do zainicjowania pęknięć i ich rozprzestrzeniania się w trakcie chłodzenia. Na podstawie przeprowadzonej analizy stwierdzono, że ciecz pojawiała się w wyniku nierównowagowego nadtapiania głównie wydzieleń fazy międzymetalicznej γ’.

EN

In the present study, the characterization of microstructural constituents in the Ni-based superalloy was carried out, as well as their role in the susceptibility to liquation cracking in heat affected zone during tungsten inert gas. The casting was characterized by considerable heterogeneity in the dendrite cores and interdendritic spaces. During scanning electron microscopy investigation significant volume fraction of cubic- and spherical-shaped precipitates of γ’ phase in dendrite cores was observed. In interdendritic spaces, as a result of the segregation of alloying elements during the solidification of the casting, eutectic γ/γ’ islands and carbides rich in refractory elements, namely Hf and Ta were also present. In the heat affected zone, heat input induced by welding led to partially dissolving of the γ’ precipitates in the surrounding γ matrix channels. A thin non-equilibrium liquid film that a appeared locally along the grain boundaries in the HAZ was a key factor in the initiation of cracks and their spreading during cooling. Based on the observation, it was found that the liquid phase appeared as a result of constitutional liquation.

8

Experimental Investigation and Multi-Response Optimization in Turning of Incoloy 800H Superalloy

Palanisamy A., Selvaraj T., Sivasankaran S.

Archives of Metallurgy and Materials

|

2018

|

Vol. 63, iss. 4

1683--1691

EN

This research work is focused on examining the turning behavior of Incoloy 800H superalloy by varying important cutting parameters. Incoloy 800H is an Iron-Nickel-Chromium based superalloy; it can withstand high temperature (810°C), high oxidization and corrosion resistance. But, it is difficult to turn in conventional machines and hence the present work was carried out and investigated. Experiments were conducted based on the standard L27 orthogonal array using uncoated tungsten inserts. The cutting force components, namely, feed force (Fx), thrust force (Fy) and cutting force (Fz); surface roughness (Ra) and specific cutting pressure (SCPR) were measured as responses and optimized using Taguchi-Grey approach. The main effects plots and analysis of mean (ANOM) were performed to check the effect of turning parameters and their significance on responses of cutting forces in all the direction (FX, FY, FZ), the surface roughness (Ra) and specific cutting pressure (SCPR). The tool wear and machined surfaces were also investigated using white light interferometer and SEM.

9

Effect of Cobalt Aluminate Content and Pouring Temperature on Macrostructure, Tensile Strength and Creep Rupture of Inconel 713C Castings

Rakoczy Ł., Grudzień M., Cygan R., Zielińska-Lipiec A.

Archives of Metallurgy and Materials

|

2018

|

Vol. 63, iss. 3

1537--1545

EN

The effect of cobalt aluminate inoculant addition and melt-pouring temperature on the structure and mechanical properties of Ni-based superalloy was studied. The first major move to control the quality of investment cast blades and vanes was the control of grain size. Cobalt aluminate (CoAl2 O4 ) is the most frequently utilized inoculant in the lost-wax casting process of Ni-based superalloys. The inoculant in the prime coat of moulds and pouring temperature play a significant role in grain size control. The finest surface grains were obtained when the internal surface of shell mould was coated with cobalt aluminate and subsequently pouring was at 1480°C. The influence of selected casting parameters and inoculant addition on mechanical properties was investigated on the basis of tensile, creep and hardness testing. The effect of grain refinement on mechanical properties were consistent with established theories. Tests conducted at ambient temperature indicated a beneficial effect of grain refinement both on tensile strength and hardness. In contrast at elevated temperature during creep, the reverse trend was observed.

10

Microstructural characterization of creep in the single crystal superalloy CMSX–4

Albrecht R., Bogdanowicz W., Gancarczyk K., Rak J., Sieniawski J., Kubiak K., Lelątko J.

Inżynieria Materiałowa

|

2017

|

Vol. 38, nr 1

15--19

EN

Blades and vanes structural components of turbine engines are processed to withstand high temperature during loading conditions of service, fulfilling high standards of quality control and safety for effective use. Therefore, characterization of mechanical properties, such as creep behaviour, are necessary for appropriate control procedures on prediction of exploitation lifetime. The materials mostly used in manufacturing of these components are single crystal nickel-base superalloys. Creep behaviour characterization, composed of creep-rupture tests, were performed on a single crystal rods made of CMSX–4 superalloy obtained at a withdrawal rate of 3 and 5 mm/min. Cylindrical rods were directly solidified in the [001] direction in an ALD Vacuum Technologies investment casting furnace (VIM-IC 2). Then, prepared specimens were tested in tensile creep under constant stress of 248 MPa at a temperature of 982°C. The longitudinal and cross sections from tested samples, were characterized by TEM and X-ray diffraction methods. It was found that all samples showed a similar rupture mechanism. The electron backscatter diffraction (EBSD) measurements showed that octahedral and cubic slip systems were present however, the critical stress was present on {111} planes. It was observed that the cubic slip has the highest calculated Schmid factor along the dendrite cores while the octahedral slip occurs through entire sample volume. Samples obtained at 5 mm/min possess a visible widening of coherent scattering regions as shown in inverse pole figures. The reason of these changes is the fact that higher rate has the greatest probability of creating small angle boundaries, often occurring in the interdendritic channels.

PL

Monokrystaliczne odlewy nadstopu niklu CMSX–4 stosuje się na najbardziej wytężone elementy silnika odrzutowego, takie jak łopatki turbiny wysokiego ciśnienia. Musza one charakteryzować się dużą żarowytrzymałością oraz żaroodpornością. Dlatego jest ważne precyzyjne określenie wpływu zjawiska pełzania na strukturę tego materiału w zależności od warunków jego wytwarzania. Celem pracy było scharakteryzowanie zmian strukturalnych oraz określenie wytrzymałości na pełzanie monokrystalicznych odlewów otrzymanych z prędkościami wyciągania formy wynoszącymi 3 oraz 5 mm/min.

11

The fixed-effects analysis of the relation between SDAS and carbides for the airfoil blade traces

Pietraszek J., Szczotok A., Radek N.

Archives of Metallurgy and Materials

|

2017

|

Vol. 62, iss. 1

235--239

EN

The primary objective was to test a usefulness of the specific fixed-effect model for the analysis of quantitative relationships gathered from the image analysis of the material microstructures. The dataset was obtained from the investigation of turbine blades made from superalloy IN713C. The analysis based on the general linear model resulted in informative plots revealing mutual relationships between secondary dendrite arm spacing and the mean plane section area of carbides in the material. Directions for further research also were obtained.

12

Metallographic Study of the Casting Made from CMSX-6 SC Nickel-Based Superalloy

Szczotok A.

Archives of Metallurgy and Materials

|

2017

|

Vol. 62, iss. 2A

581--586

EN

Microstructural characterization is an important tool to optimize the properties of engineering materials. Quantitative metallography is a common technique, which provides three-dimensional estimations of phases and structure elements from two-dimensional images. Metallography has been described as both a science and an art [1]. Superalloys are high-performance alloys which exhibits excellent mechanical strength and creep resistance at high temperatures, good surface stability, and corrosion and oxidation resistance. Temperature and corrosion resistant materials such as nickel-based superalloys are prepared mostly with standard metallographic techniques. However, the results can be significantly improved by using finely graded CMP (chemical mechanical polish) polishing solutions on a high napped polishing pad. Sample preparation requires a certain degree of skills and experience, due to the high chemical resistance of most superalloys. Some chemical solutions are able to dissolve the γ matrix and recover the γ' residue, and some others solutions can be used to obtain a contrary effect – dissolve the γ' phase precipitates and recover the γ matrix residue. The aim of the presented research is to describe qualitatively and quantitatively the as-cast microstructure of CMSX-6 SC superalloy. The author’s attention has been concentrated on the γ' phase precipitates morphology. The results of using optical and scanning electron microscopy (SEM) are presented.

13

Metallographic Study and Repeatability Analysis of γ' Phase Precipitates in Cored, Thin-Walled Castings Made from IN713C Superallo

Szczotok A., Pietraszek J., Radek N.

Archives of Metallurgy and Materials

|

2017

|

Vol. 62, iss. 2A

595--601

EN

The study describes the influence of a surface modification in cored, thin-walled castings of blades from IN-713C nickel superalloy on γ' phase precipitates. The blades were produced by using the investment casting process in the laboratory conditions as parts for a low-pressure turbine rotor. The microstructural observations of the γ' phase precipitates on the cross sections of the blades were performed. The observations were followed by quantitative metallography evaluation, and finally, a comparison of the precipitates between one blade with the conventionally applied ceramic core and one with the core covered layer contained a surface modifier (5% of CoAl2O4) was made.

14

Mikrostruktura i własności złączy naprawczych wykonanych na stopie Hastelloy X przed i po eksploatacji w turbinie gazowej

Rakoczy Ł., Zielińska-Lipiec A., Tuz L.

Przegląd Spawalnictwa

|

2016

|

R. 88, nr 4

54--56

PL

Przedmiotem badań były złącza spawane ze stopu niklu umacnianego roztworowo o nazwie handlowej Hastelloy X. Proces spawania przeprowadzono metodą GTAW (z ang. Gas Tungsten Arc Welding) na materiale w stanie dostawy oraz po eksploatacji tj. pochodzącym z turbiny gazowej. W celu porównania zmian mikrostrukturalnych i własności wykonano badania za pomocą mikroskopii świetlnej, skaningowej oraz pomiary mikrotwardości. Dodatkowo przeprowadzono badania za pomocą transmisyjnej mikroskopii elektronowej (TEM) w obszarze materiału rodzimego po eksploatacji. Wykonane badania TEM były podstawą do stwierdzenia, iż temperatura eksploatacji wpłynęła jedynie na zwiększenie ilości i średnicy wydzieleń węglików typu M6C, natomiast temperatura eksploatacji leżała poza zakresem wydzielania faz wtórnych węglików typu M23C6 i faz topologicznie zwarcie wypełnione σ lub μ. Hastelloy X w stanie przesyconym charakteryzuje się bardzo dobrą spawalnością, jednakże może ona ulec obniżeniu w wyniku obecności kruchych i niskotopliwych faz powstałych w trakcie eksploatacji.

EN

The aim of the present study was to characterize repair welds performed on solid solution strengthened nickel-based superalloy also known Hastelloy X. The welding process was performed using GTAW. Process was carried out on materials in solid solution condition (unaged state) and after long term service in gas turbine. In order to compare microstructural changes and properties of welds light microscopy, scanning electron microscopy and microhardness measurements were performed. Additionally, transmission electron microscopy (TEM) of the base material after long term service was carried out. TEM study was the basis for the conclusion that the operating temperature had an impact on increase the amount and diameter of M6C-type carbides. Operating temperature of the turbine part was too low to contribute to the precipitation of M23C6- type carbides and topologically closed packed phases σ and μ. Alloy in solid solution condition has excellent weldability but precipitation of brittle and low melting temperature constituents during service may affect the tendency to cracking.

15

Badania sił skrawania podczas frezowania superstopu Inconel 718 z podwyższoną prędkością skrawania

Bławucki S., Zaleski K., Matuszak J.

Mechanik

|

2016

|

R. 89, nr 8-9

1090--1091

PL

Skrawanie z dużą prędkością (HSM) jest coraz częściej stosowane podczas obróbki stopów trudnoobrabialnych. Strategia HSM przyczynia się do wzrostu wydajności oraz poprawy jakości obrobionej powierzchni. Zaprezentowano wyniki badań doświadczalnych frezowania z podwyższoną prędkością superstopu Inconel 718. Podjęto próbę określenia granicznej prędkości skrawania tego stopu dla obróbki HSM na podstawie kryterium sił skrawania.

EN

High Speed Machining (HSM) is widely used in the cutting of difficult to machine alloys. Application of HSM strategies leads to increase a productivity and improve a quality of the treated surface. This paper presents results of experimental research of milling Inconel 718 superalloy with increased speed. It was made an attempt to determine the boundary cutting speed for this alloy in HSM conditions, using the criterion of cutting forces.

16

Study on deformation-induced damage evolution for Inconel718 superalloy with the use of an innovative single-specimen method

Socha G., Madejski B., Malicki M.

Journal of Theoretical and Applied Mechanics

|

2016

|

Vol. 54 nr 4

1379--1390

EN

An innovative method for investigation of deformation-induced damage of elastic-plastic materials is proposed. A static tension test, performed on a specimen with a variable cross- -section gage part enabled analysis of degradation of the material structure for all stages of permanent deformation. Modified Johnson model has been used to quantify damage. Analysis of the damage of the specimen surface as well as observations of the damage induced inside the gage part of the specimen has been performed using SEM observations. Debonding at the interface between a hard inclusion and a ductile matrix has been found to be responsible for initiation of cracks on the specimen surface as well as inside the gage part of the specimen. Analysis of the subsequent void growth has been performed. Surface cracks are associated with plastic deformation resulting in an increase of the surface roughness. Variations of the specimen surface roughness have been found to be in good correlation with the damage parameter. This correlation enables the use of surface roughness as the relative damage indicator for the investigated material and deformation mode.

17

Influence of variable casting wall thickness and shell mold material and its thermal properties on secondary dendrite arm spacing in IN 713C superalloy castings

Szczotok A.

Inżynieria Materiałowa

|

2016

|

Vol. 37, nr 5

217--222

EN

The results of microstructure investigations of IN 713C superalloys obtained as thin walled‚ wedge’ castings from three kinds of shell molds are presented. Light microscopy, scanning electron microscopy observations and secondary dendrite arm spacing (SDAS) measurements were used to determine the differences in the IN 713C castings obtained using three kinds of shell mold materials. The effects of major constituents of the three shell molds: zirconium silicate ZrSiO4, aluminosilicate mAl2O3 . nSiO2 and SiC-based system on the SDAS in the investigated castings of the IN 713C superalloy are described. The results confirm that crystallization conditions (the variable wall thickness of the casting and material of the shell) of the IN 713C castings influence their microstructure. The increased SiC content in the shell molds has an effect on the crystallization process kinetics as indicated by the changes in the observed secondary dendrite arm spacing.

PL

Powszechnie wiadomo, że parametry procesu odlewania mogą wpływać na mikrostrukturę i właściwości mechaniczne nadstopów na osnowie niklu. Zmniejszenie odległości między ramionami wtórnymi dendrytów (SDAS) prowadzi do zredukowania porowatości i obszarów eutektyki w odlewie. Celem przeprowadzonych badań było ustalenie wpływu grubości ścianki odlewu oraz składu materiału i właściwości cieplnych formy ceramicznej na odległości między ramionami wtórnymi dendrytów w odlewach z nadstopu IN 713C.

18

Evaluation of the fatigue damage development using ESPI method

Kopeć M., Grzywna P., Kukla D., Kowalewski Z.

Inżynieria Materiałowa

|

2016

|

Vol. 37, nr 4

201--205

EN

Fatigue damage process developing in structural materials under long-term cyclic loading is still an unsolved problem of modern engineering. Attempts to assess a degree of materials degradation under fatigue conditions on the basis of changes in the areas of local strain concentration determined by optical methods can be treated as the promising contemporary research direction of majority of scientific centres in the world. In most cases, fatigue damage has a local character and it is based on damage development leading to generation of cracks appearing around structural defects or geometrical notches. An identification of these areas and their subsequent monitoring requires a full-field displacement measurements performed on the objects surfaces. It seems that modern contemporary optical methods for displacement components measuring on the surfaces of structural elements or tested specimens are suitable for such purpose. Digital Image Correlation (DIC) and Electronic Speckle Pattern Interferometry (ESPI) are nowadays the most widely used testing methods in this area. Both of them enable capturing of displacement and strain components distributions. This paper presents an attempt to use the ESPI method for fatigue damage evaluation and its monitoring on specimens made of the aluminide coated nickel super-alloys. Flat specimens were subjected to cyclic loading. The fatigue tests were interrupted several times in order to perform a static loading during which the optical measurements were carried out. An analysis of the results captured by the ESPI system allowed indication of places of the greatest stress concentration and demonstration of the damage development process as a function of the increasing number of cycles.

PL

Proces niszczenia materiału w trakcie badań zmęczeniowych pod wpływem długotrwałych obciążeń eksploatacyjnych od lat pozostaje jednym z głównych problemów poruszanych przez wiele ośrodków badawczych na świecie. W większości przypadków zmęczenie materiału wykazuje lokalny charakter prowadzący do powstawania pęknięć występujących wokół defektów struktury czy karbów geometrycznych. Identyfikacja tych obszarów i ich późniejsza obserwacja wymagają użycia polowych technik pomiarowych takich jak cyfrowa korelacja obrazu (Digital Image Correlation, DIC) lub elektroniczna interferometria plamkowa (Electronic Speckle Pattern Interferometry, ESPI). Pozwalają one określać rozkłady składowych przemieszczenia, odkształcenia i naprężenia na powierzchni próbki (rys. 1). Stosowanie ich w trakcie badań zmęczeniowych umożliwia lokalizację miejsca największej koncentracji naprężenia wywołanej defektami próbek oraz pozwala z dużą dokładnością przewidzieć miejsce inicjacji uszkodzenia. Celem pracy jest obserwacja i analiza rozwoju pękania zmęczeniowego wywołanego długotrwałymi, cyklicznymi obciążeniami za pomocą optycznej metody pomiaru składowych przemieszczenia ESPI.

19

Characterization of IN713C superalloy microstructure after high temperature creep test by LM, SEM and STEM

Szczotok A., Kościelniak B.

Inżynieria Materiałowa

|

2016

|

Vol. 37, nr 2

50--58

EN

This work focuses on the influence of creep phenomenon on the cast IN713C nickel-based superalloy. The carrot-shape IN713C superalloy castings were produced in an investment casting cluster mould and the creep test samples were then prepared from the castings. The creep tests were carried out in order to investigate processing–microstructure–property relationships. The resultant macro- and microstructures were observed and characterized after the creep tests using light microscopy, scanning electron microscopy and scanning transmission electron microscopy. The aim of the analysis was to reveal the changes in the microstructure that occurred as a result of the creep and to identify the phases that participate in voids formation, and crack generation and propagation during the creep tests. It was confirmed that the creep resistance of the IN713C superalloy is negatively affected by some structural characteristics such as porosity, (γ + γ′) eutectic or carbide precipitates along the grain boundaries. Our work confirms that a combination of thermal conditions with a tensile force affected the microstructure of IN713C nickel-based superalloy causing changes in morphologies of the existing precipitations and phase transformations, as in the case of the carbides. Additionally, carbide sulphides containing primarily Zr and intermetallic phase including mainly Ni and Zr were observed.

PL

Artykuł dotyczy wpływu zjawiska pełzania na strukturę odlewniczego nadstopu na osnowie niklu IN713C. Makro- i mikrostrukturę materiału uzyskaną w efekcie przeprowadzonej próby pełzania obserwowano przy różnych powiększeniach. Celem badań było ujawnienie zmian struktury, jakie pojawiły się w efekcie pełzania i zidentyfikowanie faz, które brały udział w powstawaniu nieciągłości materiału oraz generowaniu i propagacji pęknięć podczas próby pełzania.

20

Wybrane właściwości połączeń superstopu Haynes H 230 przy użyciu mikrospawania opornościowo impulsowego

Depczyński W., Młynarczyk P., Spadło S., Śliwa E.

TTS Technika Transportu Szynowego

|

2015

|

R. 22, nr 12

370--373, CD

PL

Celem pracy było przeanalizowanie mikrostruktury i własności mechanicznych połączenia mikrospawanego blach cienkich z superstopu HAYNES H230. Połączenia zostały wykonane przy użyciu urządzenia do mikrospawania WS 7000S. W części badawczej przeanalizowano skład chemiczny oraz strukturę wybranego materiału podstawowego, z którego przygotowano próbki do dalszych badań. Dla scharakteryzowania właściwości uzyskanej spoiny zostały przeprowadzone badania własności mechanicznych - pomiar mikrotwardości, wytrzymałość na rozciąganie oraz obserwacja mikrostruktury na zgładach metalograficznych za pomocą mikroskopu metalograficznego. Obserwację wykonano na zgładach trawionych. Cel praktyczny badań stanowiło dobranie optymalnych parametrów spawania zapewniających najwyższe własności mechaniczne otrzymanych złączy. Po przeanalizowaniu otrzymanych wyników ustalono optymalne parametry procesu i wyciągnięto stosowne wnioski.

EN

The article presents preliminary results of microwelding thin sheet occurred of superalloy H 230. There were shown the possibilities of combining thin metal sheet using resistive pulse microwelding. The joints were made using a device to microwelding SST WS 7000s. For characterizing of the obtained weld tests properties there were examined mechanical properties like: measuring the microhardness, stretching test and microstructure observation. Microhardness measurements of the joints and base material where taken using Matsuzawa Vickers MX 100 type with applied load 100G (0,98 N). Stretching test where made on Zwick/Roell Z100 machine with applied load 10kN. To observe mentioned joints, metallographic microscope Nikon Eclipse MA2000 was used. The studies determined the basic parameters of microwelding thin sheet of joint made and the quality of the weld. The results showed that there is a possibility of obtaining the satisfying quality joint using micro welding between the thin sheet from superalloy H 230.