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Number of results: 10
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Abstract

The presented access the influence of Mn content (0-0.94 wt.%) on the course of the cooling curves, phase transformation, macrostructure, and microstructure of Al-Cu alloys for three series: initial (Series I), with the addition of an AlTi master (Series II), and modified with AlTi5B1 (Series III). The maximum degree of undercooling ΔT was determined based on the cooling curves. The surface density of the grains (NA) was determined and associated with the inverse of solidification interval 1/ΔTk. Titanium (contained in the charge materials as well as the modifier) has a significant effect on the grinding of the primary grains in the tested alloys. A DSC thermal analysis allowed for the determination of phase transition temperatures under conditions close to equilibrium. For series II and III, the number of grains decreases above 0.2 wt.% Mn with a simultaneous increase in solidification interval 1/ΔTk. The presence of Al2Cu eutectics as well as the Cu-, Fe-, and Mn-containing phases in the examined samples was demonstrated using scanning electron microscopy.

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Authors and Affiliations

S. Stąpór
M. Górny
M. Kawalec
B. Gracz
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Abstract

Paper presents the results of evaluation of heat resistance and specific heat capacity of MAR-M-200, MAR-M-247 and Rene 80 nickel

superalloys. Heat resistance was evaluated using cyclic method. Every cycle included heating in 1100°C for 23 hours and cooling for 1

hour in air. Microstructure of the scale was observed using electron microscope. Specific heat capacity was measured using DSC

calorimeter. It was found that under conditions of cyclically changing temperature alloy MAR-M-247 exhibits highest heat resistance.

Formed oxide scale is heterophasic mixture of alloying elements, under which an internal oxidation zone was present. MAR-M-200 alloy

has higher specific heat capacity compared to MAR-M-247. For tested alloys in the temperature range from 550°C to 800°C precipitation

processes (γ′, γ′′) are probably occurring, resulting in a sudden increase in the observed heat capacity.

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Authors and Affiliations

R. Przeliorz
M. Góral
P. Gradoń
F. Binczyk
T. Mikuszewski
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Abstract

Archaeometallurgical investigations presented in this work focus on analysing the microstructure as well as mechanical properties of artefacts from the17th in form of findings performed from cast iron as well as copper casts. The presented research results extend the up-to-date knowledge and present the analysis of structural compounds found in the microstructure of the artefacts from the time dating back to the late Middle Ages in the region around Czestochowa, Poland. The tested samples were found in earth in the city centre under the present marketplace. The excavation works were carried out in summer in the year 2009, and have resulted in the excavation of artefacts in form of copper block of the weight of several kg. The excavation action was led by a group of Polish archaeologists collaborating with the local authorities. The performed pre-dating of this element determines the age of the artefacts as the 17th century AD. The excavations that have been taking place since 2007 have widened the knowledge of the former Czestochowa. Historians of this town have suggested, that the found weight and traces of metallurgical activity suggest that the exposed walls were an urban weight. The weight is visible on the 18th century iconography. What was find on the Old Market indicates that there was a lush economic life before the Swedish invasion in this part of Poland. Some buildings lost their functions or were changed, others died in fires, but new places developed. To describe the microstructure, with its structural components, research was done using microscopy techniques, both of the light as well as electron microscopy (SEM), also chemical composition analysis was carried out using the EDS technique, as well as tool for phase analysis were applied in form of X-Ray Diffraction (qualitative analysis), especially for the reason to describe the phases present in the excavated material. This research will help to obtain new information in order to investigate further archaeometallurgical artefacts, extending the knowledge about middle age metallic materials its usage and manufacturing.
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Authors and Affiliations

Ł. Wierzbicki
J. Konieczny
K. Labisz
K. Głowik-Łazarczyk
S. Surma
S. Jurczyk
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Abstract

The scope of this work is to investigate the precipitation of two Al-Mg-Si alloys with and without Cu and excess Si by using the differential scanning calorimetry (DSC), transmission electron microscopic (TEM), Vickers hardness measurement and X-ray diffraction. The analysis of the DSC curves found that the excess Si accelerate the precipitation and the alloy contain the excess Si and small addition of copper has higher aging-hardness than that of free alloy (without excess Si and Cu) at the same heat treatment condition. The sufficient holding time for the precipitation of the β'' phase was estimated to be 6 hours for the alloy aged at 100°C and 10 hours for the alloy aged at 180°C. The low Copper containing Al-Mg-Si alloy gives rise to the forming a finer distribution of β (Mg2Si) precipitates which increases the hardness of the alloy. In order to know more about the precipitation reactions, concern the peaks on the DSC curve transmission electron microscopy observation were made on samples annealed at temperatures (250°C, 290°C and 400°C) just above the corresponding peaks of the three phases β'', β' and β respectively.

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Authors and Affiliations

Hanna Belghit
Hichem Farh
Toufik Ziar
Mosbah Zidani
Meryem Guemini
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Abstract

The article presents the results of research on selected thermal, mechanical properties, as well as the microscopic structure of filaments and details made on a 3D printer in FDM technology. The materials used in the study were PETG (polyethylene terephthalate doped with glycol) and PLA (polylactide) doped with copper. As part of the study, Differential Scanning Calorimetry (DSC) was performed in order to determine the temperatures of phase transformations and changes in melting enthalpy values of filaments before the printing process and also elements made of them. The second part of the research was electrocorrosive ageing process of printouts, carried out in the Simulated Body Fluid solution in a device generating 0.3 A direct current, voltage with value 4.3 V for the entire duration of the test, which was 720 h. After this process DSC test was conducted again. The next stage of the research was Dynamic Mechanical Analysis (DMA) of printouts before and after electrocorrosive ageing process. This test was carried out to characterize the dynamic-mechanical properties as a function of frequency, temperature and time. Additionally, microscopic analyses of the surfaces of the tested printouts were performed in order to assess the changes after electrolysis.
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Authors and Affiliations

J. Redutko
1
ORCID: ORCID
A. Kalwik
1
ORCID: ORCID
A. Szarek
1
ORCID: ORCID

  1. Czestochowa University of Technology, Faculty of Mechanical Engineering and Computer Science, Department of Technology and Automation, 21 Armii Krajowej Av., 42-201 Czestochowa, Poland
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Abstract

TiNi alloys have excellent shape memory properties and corrosion resistance as well as high biocompatibility. This study investigated the effects of copper addition on the phase transitions and electrochemical corrosion behaviors of Ti50Ni50-xCux alloys. TiNi, Ti50Ni47Cu3, Ti50Ni44Cu6, and Ti50Ni41Cu9 alloys were prepared using vacuum arc remelting followed by 4 h homogenization at 950°C. Differential scanning calorimetry and X-ray diffraction analyses were conducted. The corrosion behaviors of the alloys were evaluated using potentiodynamic polarization test in Hank’s balanced salt solution at a temperature of 36.5 ± 1°C. The TiNi alloy showed phase transitions from the cubic B2 phase to the monoclinic B19’ phase when the alloy was thermally cycled. The addition of copper to the TiNi alloy played a major role in stabilizing the orthorhombic B19 phases during the phase transitions of Ti50Ni50-xCux alloys. The shifts in the corrosion potential toward the positive zone and the low corrosion current density were affected by the amount of Cu added. The corrosion resistance of the TiNi alloy increased with increasing copper content.

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Authors and Affiliations

Kwangmin Lee
ORCID: ORCID
Sanghyun Rho
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Abstract

The aim of these studies was to obtain single phase cubic modification of Li7La3Zr2O12 by mechanical milling and annealing of La(OH)3, Li2CO3 and ZrO2 powder mixture. Fritsch P5 planetary ball mill, Rigaku MiniFlex II X-ray diffractometer, Setaram TG-DSC 1500 analyser and FEI Titan 80-300 transmission electron microscope were used for sample preparation and investigations. The applied milling and annealing parameters allowed to obtain the significant contribution of c-Li7La3Zr2O12 in the sample structure, reaching 90%. Thermal measurements revealed more complex reactions requiring further studies.

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Authors and Affiliations

D. Oleszak
B. Kurowski
T. Pikula
M. Pawlyta
M. Senna
H. Suzuki
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Abstract

The thermal reclamation process as a utilisation method of spent moulding and core sands is more costly than other reclamation methods, but in the majority of cases it simultaneously provides the best cleaning of mineral matrices from organic binders. Thus, the application of the thermal analysis methods (TG-DSC), by determining the temperature range within which a degradation followed by a destruction of bounded organic binders in moulding sands, can contribute to the optimisation of the thermal reclamation process and to the limiting its realisation costs. The thermal analysis results of furan resin, one of the most often applied binder in foundry practice, are presented in the hereby paper. The influence of the heating rate of the sample - placed in the thermal analyser - on its degradation and destruction process under oxygen-free (argon) and oxygen (air) conditions, were compared. The recorded TG and DSC curves were used for analysing these processes as the temperature as well as the time function. The obtained results were analysed with regard to determining the required temperature of the thermal reclamation of the investigated organic binder. The usefulness of the developed methodology was found out, however under conditions of meeting several essential requirements concerning the repeatability of performed analyses.

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Authors and Affiliations

M. Łucarz
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Abstract

Paper presents the results of ATD and DSC analysis of two superalloys used in casting of aircraft engine parts. The main aim of the

research was to obtain the solidification parameters, especially Tsol and Tliq, knowledge of which is important for proper selection of

casting and heat treatment parameters. Assessment of the metallurgical quality (presence of impurities) of the feed ingots is also a very

important step in production of castings. It was found that some of the feed ingots delivered by the superalloy producers are contaminated

by oxides located in shrinkage defects. The ATD analysis allows for quite precise interpretation of first stages of solidification at which

solid phases with low values of latent heat of solidification are formed from the liquid. Using DSC analysis it is possible to measure

precisely the heat values accompanying the phase changes during cooling and heating which, with knowledge of phase composition,

permits to calculate the enthalpy of formation of specific phases like γ or γ′.

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Authors and Affiliations

P. Gradoń
F. Binczyk
J. Cwajna
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Abstract

With the use of differential scanning calorimetry (DSC), the characteristic temperatures and enthalpy of phase transformations were

defined for commercial AlSi9Cu3 cast alloy (EN AC-46000) that is being used for example for pressurized castings for automotive

industry. During the heating with the speed of 10oCmin-1

two endothermic effects has been observed. The first appears at the temperature

between 495 oC and 534 oC, and the other between 555 oC and 631 oC. With these reactions the phase transformation enthalpy comes up as

+6 J g-1

and +327 J g-1

. During the cooling with the same speed, three endothermic reactions were observed at the temperatures between

584 oC and 471 oC. The total enthalpy of the transitions is – 348 J g-1

.

Complimentary to the calorimetric research, the structural tests (SEM and EDX) were conducted on light microscope Reichert and on

scanning microscope Hitachi S-4200. As it comes out of that, there are dendrites in the structure of α(Al) solution, as well as the eutectic

(β) silicon crystals, and two types of eutectic mixture: double eutectic α(Al)+β(Si) and compound eutectic α+Al2Cu+β.

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Authors and Affiliations

J. Piątkowski
R. Przeliorz
A. Gontarczyk

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