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1

The influence of carbide reinforcement on the properties of sintered aluminium alloy matrix composites

Szewczyk-Nykiel Aneta

Technical Transactions

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2023

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Vol. 120, iss. 1

art. no. e2023005

EN

Based on the commercial aluminium alloy powder blend (Alumix 431D) metal matrix composites reinforced with particles of SiC as well as TiC were produced by conventional powder metallurgy technology and the effect of the type and amounts of reinforced particles on the selected properties and microstructure of sintered composites were investigated. In particular, the densification behaviour, the wear resistance and the corrosion resistance in 3.5% NaCl solution were identified. It was stated that both the type and the weight fraction of carbide used as particulate reinforcement have a great impact on the properties of aluminium alloy matrix composites. It was shown that the introduction of titanium carbide has a more favourable effect on the properties of sintered Alumix 431D matrix composites in comparison to silicon carbide and the optimum content of TiC in composite is 4 wt. % due to the highest hardness, wear resistance (wear rate of 2.865·10 ̄ ³ mm³/m) and simultaneously the best corrosion resistance (corrosion rate of 0.005 mm/year).

2

The microstructures of in-situ synthesized TiC by Ti-CNTs reaction in Cu melts

Xu Xuexia, Wang Yong, Wang Qing, Dong Guozhen, Li Wenbin, Li Guowei, Lv YaDong, Zhang Jin, Ding Haimin

Materials Science Poland

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2022

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Vol. 40, No. 1

145--158

EN

In order to study the influence of the carbon nanotubes (CNTs) as a source of carbon on the microstructure of in-situ synthesized TiC in Cu melts, CNTs and Ti powders were introduced into melted Cu to prepare TiC-reinforced Cu matrix composites. The influence of Ti/C ratio and Si on the microstructures and properties of the composites were also examined. It is found that CNTs can be effectively wetted through the Ti-C reaction and successfully introduced into Cu melt to synthesize TiC. In examining the changes in Ti/C ratio, it was found that an increase in the Ti content may result in the decrease of TiC agglomeration and improvement of TiC dispersion, while simultaneously causing an increase in the TiC particle size. Besides, while the addition of Si into Ti-CNTs mixture can also improve the distribution of TiC, the effect is weak compared with that of increasing the content of Ti. It was also found that the highest hardness (238.8 HV) is achieved by the Cu-Ti-C composite with the highest Ti/C ratio, while the electrical conductivities of all the prepared composites are relatively low, which should be due to the insufficient reaction between Ti and CNTs.

3

Evaluation of the Mechanical and Electrical Properties of Spark Plasma Sintered Titanium Carbide Reinforced Alumina Ceramic Composite

Selvakumar G., Prakash S. Ram, Rajkumar K.

Archives of Metallurgy and Materials

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2021

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Vol. 66, iss. 3

831--838

EN

Spark Plasma Sintering (SPS) is identified as a suitable technique to prepare the alumina titanium carbide composite to overcome the difficulty in fabricating it through other consolidation method. The present work focuses on the fabrication and characterization of a series of titanium carbide reinforced alumina ceramic composites using a spark plasma sintering process. The titanium carbide reinforcement on the alumina matrix is varied between 20 and 35 wt.%, in order to improve the electrical conductivity and fracture toughness of the composites. The particle size of the starting powders at received and ball milled conditions was analysed through Particle size analyser and Scanning Electron Microscope (SEM). Microstructural analysis revealed that the TiC reinforcement is uniformly dispersed in the sintered composite. XRD report showed that α-alumina and titanium carbide were the two dominant phases without the formation of any reaction phases. Further, the correlation between mechanical and physical properties of the prepared composite was investigated as a function of TiC. Various fracture toughening indicators like crack deflection, bridging and branching were analysed by Vicker’s indentation method. Electrical resistivity of the sintered compact decreases proportionally with the increase in titanium carbide constituents. Maximum density (98.80%) and hardness (20.56 GPa) was obtained for 30 wt. % reinforced composite. Almost 40% improvement in fracture toughness is noted for 25 wt. % reinforced composite. This work demonstrates the synthesis and fabrication of alumina titanium carbide composites at low temperature via SPS resulted in obtaining an intact compact with improved mechanical and electrical properties.

4

Local composite reinforcements of TiC/FeMn type obtained in situ in steel castings

Olejnik E., Szymanski L., Tokarski T., Opitek B., Kurtyka P.

Archives of Civil and Mechanical Engineering

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2019

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Vol. 19, no. 4

997--1005

PL

This dissertation concerns the method of obtaining the in situ local composite reinforce- ments (LCR – Locally Composite Reinforcement) of the TiC–FeMn type in steel castings. The reinforcing phase – titanium carbide (TiC) was obtained by placing the pressed substrates of the synthesis of TiC in the form of compacts into a mold cavity. The basic problem connected with fabricating TiC local composite reinforcements is the phenomenon of fragmentation. In order to reduce this phenomenon, a moderator composed of Hadfield steel at 70 and 90% by weight was introduced to the initial mixture of the TiC substrate powder. As a result, homogenous and dimensionally stable composite reinforcements of the austenite matrix were obtained and examined by analyzing their macrostructure, microstructure, structure, hardness, and wear resistance. An investigation of the phase analysis and microstructure confirmed the presence of the TiC phase in the structure of the composite zones. The hardness of the composite reinforcement ranged from 550 HV to 800 HV30 depending on the proportion between the percentage of the moderator and the content of the pure substrates of the synthesis reaction of the TiC.

5

Strefy kompozytowe otrzymywane in situ w staliwnych odlewach bijaków do kruszarek

Opitek B., Olejnik E., Lelito J.

Prace Instytutu Odlewnictwa

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2018

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Vol. 58, no. 3

191--199

PL

Prezentowana praca miała na celu uzyskanie elementu bijaka do kruszarki wykorzystywanego w warunkach dużego zużycia ściernego oraz pracującego pod wysokimi naciskami. Wytworzono, metodą SHSB, lokalną strefę kompozytową składającą się z bardzo twardego węglika tytanu – TiC. Umieszczone w przygotowanej wcześniej formie odlewniczej wypraski zostały zalane ciekłym metalem, którego ciepło spowodowało zainicjowanie reakcji in situ tworzenia się węglika tytanu. Otrzymany w ten sposób odlew poddano badaniom. Wykonano analizę składu fazowego na dyfraktometrze rentgenowskim – XRD. Dodatkowo przeprowadzono badania na elektronowym mikroskopie skaningowym – SEM w celu określenia kształtu, wielkości i rozmieszczenia TiC. W efekcie przeprowadzonych prac i badań otrzymano materiał wysokiej jakości zgodny z oczekiwaniami.

EN

The aim of the presented study was to obtain the element of a crushing mill beater reinforced with a composite zone, working under the conditions of high abrasive wear as well as high pressures. By means of the SHSB method, a local composite zone was created consisting of very hard titanium carbide – TiC. The moulded pieces prepared beforehand in the casting mould were filled with liquid metal, whose heat caused the initiation of an in situ reaction – the formation of titanium carbide. The cast obtained in this way was subjected to tests. An analysis of the physical composition was performed on an X-ray diffractometer – XRD. Additionally, investigations with the use of a scanning electron microscope SEM were carried out in order to determine the shape, size and distribution of TiC. As a result of the conducted research, a high quality material was obtained, which was in line with the authors' expectations.

6

Stosowalność kwasu borowego do wytwarzania nanokompozytów TiB2/TiC/ZrO2 r.s. metodą in situ

Moskała N., Pyda W.

Materiały Ceramiczne

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2018

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T. 70, nr 4

371--389

PL

Ocenie poddano przydatność użycia kwasu ortoborowego do wytwarzanie metodą in situ nanometrycznych wtrąceń TiB2 i TiC w tetragonalnej osnowie tlenku cyrkonu. Kwas ortoborowy, żywicę fenolowo-formaldehydowę i nanoproszek cyrkoniowy stabilizowany 2,5% mol. Y2O3 i domieszkowany 18% mol. TiO2 zastosowano do syntezy wtrąceń TiB2 i TiC w cząstkach tlenku cyrkonu, którą prowadzono w zakresie 1100-1600 °C w próżni. Tak otrzymane proszki kompozytowe zawierały nanocząstki TiB2 i TiC o rozmiarach odpowiednio 60-80 nm i 25-40 nm. Proszki kompozytowe spiekano w temperaturze 1500 °C w próżni, aby uzyskać gęste materiały kompozytowe. Szczegółowej charakterystyce poddano skład fazowy proszków i kompozytów, zmierzono rozmiar cząstek TiB2 i TiC w proszkach, określono stan zagęszczenia spieków, zbadano mikrostrukturę i wybrane właściwości kompozytów. Właściwości mechaniczne kompozytów porównano z materiałem 3Y-TZP. Zbadano wpływ temperatury syntezy in situ na skład fazowy proszków i spieków oraz na właściwości mechaniczne kompozytów, wskazując rolę jaką pełni kwas ortoborowy w kształtowaniu się tych właściwości. Otrzymano gęste kompozyty z przewagą fazy tetragonalnej w osnowie cyrkoniowej, zawierające submikronowe i w części nanometryczne wtrącenia TiB2 i TiC, które charakteryzowały się podwyższoną odpornością na zużycie ścierne.

EN

The applicability of the use of orthoboric acid to production of nanometric inclusions of TiB2 and TiC in the tetragonal zirconium oxide matrix by the in situ method was evaluated. Orthoboric acid, phenol-formaldehyde resin and zirconia nanopowder stabilized with 2.5 mol% Y2O3 and doped with 18 mol% TiO2 were used for the synthesis of TiB2 and TiC inclusions in zirconia particles, which was carried out at 1100-1600 C in vacuum. The composite powders thus obtained contained TiB2 and TiC nanoparticles with sizes of 60-80 nm and 25-40 nm, respectively. Composite powders were sintered at 1500 C under vacuum to obtain dense composite materials. The phase composition of powders and composites was characterized in detail, the particle size of TiB2 and TiC in powders was measured, the state of compacting of sinters was determined, the microstructure and selected properties of composites were examined. The mechanical properties of the composites were compared with the 3Y-TZP material. The influence of the in situ synthesis temperature on the phase composition of powders and sinters as well as the mechanical properties of composites was examined, indicating the role of orthoboric acid in the formation of these properties. Dense composites with predominance of the tetragonal phase in the zirconium matrix were obtained, containing submicron and in part nanometric inclusions of TiB2 and TiC, which were characterized by increased resistance to abrasion.

7

Microstructure and Properties of TiC/Ti Coatings Deposited by the Supersonic Cold Gas Spray Technique

Kusiński J., Kac S., Kowalski K., Dosta S., Georgiou E. P., Garcia-Forgas J., Matteazzi P.

Archives of Metallurgy and Materials

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2018

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Vol. 63, iss. 2

867--873

EN

Nanostructured, biocompatible, TiC/Ti Supersonic Cold Gas Sprayed coatings were deposited onto a Ti6Al4V alloy and their microstructure, wear resistance and hardness were investigated. The starting nanostructured powder, containing a varied mixture of Ti and TiC particles, was produced by high energy ball milling. Scanning and transmission electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction were used for structural and chemical analyses of powder particles and coatings. Coatings, 250-350 μm thick, preserving the nanostructure and chemical powder composition, with low porosity and relatively high hardness (~850 HV), were obtained. These nanostructured TiC/Ti coatings exhibited better tribological properties than commonly used biomedical benchmark materials, due to an appropriate balance of hard and soft nano-phases.

8

Comparison of the structure and topography of selected low friction thin films

Paradecka A., Lukaszkowicz K., Kříž A., Potempa R.

Journal of Achievements in Materials and Manufacturing Engineering

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2017

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Vol. 83, nr 1

21--25

EN

Purpose: The purpose of this article is to characterize and compare the structure, mechanical and tribological properties of low friction DLC and TiC thin films deposited on the austenitic steel X6CrNiMoTi17-12-2 substrate. Design/methodology/approach: In the research, the samples of the DLC and TiC thin films with transition hard AlCrN interlayer deposited by magnetron sputtering and PACVD technology respectively were used. Observations of topography were made using a scanning electron microscope (SEM), and the atomic force microscope (AFM). The structure of samples was performed using a Raman microscope. The microhardness tests of thin films were made by Oliver & Phare method. Findings: Studies confirmed that the combination of research SEM and AFM provide crucial information on the structure and topography of the samples. It was possible to obtain information about the topography parameters and allow for the assessment of morphology and quality of the tested coatings. Study of the structure using Raman spectroscopy revealed the band corresponding to the DLC and TiC thin films. Practical implications: The current application areas for low friction thin films are constantly growing, and the intensive development of techniques requires the use of new technologies what leads to the production of the specific surface layer and a thorough examination. Originality/value: Growing area of low friction coatings with specific properties requires the use of specialized tools aimed at assessing the topography and structures which are responsible for tribological properties.

9

Structure and phase composition of newly developed high manganese X98MnAlSiNbTi24–11 steel of TRIPLEX type

Sozańska-Jędrasik L., Mazurkiewicz J., Borek W., Dobrzański L. A.

Inżynieria Materiałowa

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2017

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Vol. 38, nr 2

69--76

EN

The work presents the results of investigations of the structure and phase composition of newly developed high manganese X98MnAlSiNbTi24–11 steel of TRIPLEX type. The average density of such steel is 6.67 g/cm3, which is less than for typical structural steels by even 15%. A preliminary analysis of phase composition and structure allows to find an austenitic γ-Fe(Mn, Al, C) structure in the investigated steel with uniformly distributed ferritic α-Fe(Mn, Al) areas elongated towards the boundaries of austenite grains and numerous carbides with differentiated chemical composition and varied size. Nb- and Ti-based complex carbides are dominant in the steel. The investigations of the chemical composition of the carbides revealed in the matrix allow to identify with high probability dispersive κ-(Fe, Mn)3AlC carbides with the nanometric size of approx. 10÷160 nm, which has to be yet confirmed with electron transmission microscopy methods. Fe, Mn and Al as well as small amounts of Nb, Ti and Si are contained in such carbides. The occurrence of aluminium carbonitrides with a fraction of Nb and Ti was also revealed. The size of the above Nb and Ti carbides revealed in solid specimens in the matrix of the studied steel is between approx. 10 nm to 15 μm. X-ray diffraction examinations of carbide isolates prepared by the method of chemical dissolution in HCl showed the existence of NbTiC2 carbides in the studied steel. The diffraction examinations of solid specimens revealed, apart from austenite and ferrite, also the existence of TiC carbides and such initially classified as Mn3.6C0.4 type.

PL

Celem pracy była charakterystyka struktury i składu fazowego nowoopracowanej stali wysokomanganowej X98MnAlSiNbTi24–11 typu TRIPLEX zawierającej dodatki stopowe Ti i Nb przy dużej zawartości węgla.

10

Microstructural Evolution During Laser Surface Alloying of Ductile Cast Iron with Titanium

Janicki D.

Archives of Metallurgy and Materials

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2017

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Vol. 62, iss. 4

2425--2431

EN

Diode laser surface alloying process was used to the in-situ synthesis of TiC-reinforced composite surface layers on the ductile cast iron substrate. The obtained composite surface layers were investigated using optical and scanning electron microscopy, and XRD diffraction. It was found that the morphology and fraction of TiC phase is directly dependent upon both the concentration of titanium in the molten pool and also the solidification rate. With increasing titanium content, the fraction of TiC increases, whereas the fraction of cementite decreases. The TiC phase promotes a heterogeneous nucleation of primary austenite grains, what reduces a tendency of cracking in the alloyed layers.

11

Microstructure Characteristic of TiC-Reinforced Cast Steel after GTAW Remelting

Sobula S., Kwiecień A., Olejnik E., Pałka P.

Archives of Foundry Engineering

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2017

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Vol. 17, iss. 4

151--154

EN

In this study, low-carbon cast steel was reinforced with TiC by SHS-B method, also known as combustion synthesis during casting method. The composite zone was then subjected to surface remelting by Gas Tungsten Arc Welding (GTAW) method. The remelting operation was realized manually, at 150 A current magnitude. Microstructure, phase composition and hardness of remelted zone were investigated. XRD results reveal that the phases of the composite zone in initial state consist of TiC and Feα. Surface remelting resulted in formation of thick layers containing TiC carbides, Feα and Feγ. Microstructural examination has shown strong refinement of titanium carbides in remelted zone and complete dissolution of primary titanium carbides synthetized during casting. The average diameter of carbides was below 2 μm. The structural changes are induced by fast cooling which affects crystallization rate. The hardness (HV30) of the remelted layer was in the range between 250 HV and 425 HV, and was lower than hardness in initial state.

12

WC-Co coatings and sinters modified with nano-sized tic microstructure – quantitative evaluation

Myalska H., Dybowski B., Moskal G.

Advances in Science and Technology. Research Journal

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2017

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Vol. 11, no 1

220--231

EN

The different concepts of WC-Co thermally sprayed coatings improvement may be considered and the application of nanoparticles, as the mechanical strengthening addition, is one of them. Nanostructured WC-Co coatings are characterized by higher hardness than the coatings formed from micrometric WC grains; whereas coatings with bimodal distribution of particles reveal greater wear resistance than the coatings obtained exclusively from nano-sized powders. Mixed effect of the matrix reinforcement by nanoparticles and strong fix of the micron-sized WC grains was proposed as a possible reason for enhanced wear resistance of bimodal coatings. In order to obtain a bimodal distribution of particles in the material standard WC-Co (83-17) powder was mixed with nanometric TiC powder (40–100 nm). The amount of TiC in powder mixtures was in the range from 1 to 7 wt.%. The mixtures were deposited on steel substrate using HVAF method and also hot pressed in vacuum. The microstructure of obtained coatings and sinters was quantitatively evaluated. Sinters revealed more homogenous distribution of the nano-sized TiC particles than the coatings. The addition of nano-sized TiC in the case of coatings has led to the decrease of its porosity. The agglomeration of nano-sized TiC particles in the coatings results in the decrease of material’s hardness.

13

Analiza wpływu zawartości TiC w nanokompozycie na topografię powierzchni po obróbce frezowaniem

AlMangour B., Grzesiak D., Dudzińska S., Grochała D., Bachtiak-Radka E.

Mechanik

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2016

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R. 89, nr 8-9

1210--1211

PL

W pracy autorzy opisują wyniki badań skrawalności nanokompozytu umocnionego węglikiem tytanu (TiC). Analizie poddano w szczególności wpływ ilości nanokrystalicznej fazy umacniającej na zmiany wybranych parametrów topografii powierzchni po frezowaniu przy zachowaniu stałych wartości technologicznych parametrów skrawania.

EN

The results of studies on machining of nanocomposite reinforced by titanium carbide (TiC) have been described. The influence of the reinforcement phase share on the variability of selected parameters of the surface topography at constant machining parameters was the main subject of the analysis.

14

Locally Reinforcement TiC-Fe Type Produced in Situ in Castings

Olejnik E., Szymański Ł., Kurtyka P., Tokarski T., Maziarz W, Grabowska B., Czapla P.

Archives of Foundry Engineering

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2016

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Vol. 16, iss. 3

77--82

EN

Refinement is one of the most energy consuming technological process, aimed at obtaining mineral raw materials of the proper grain size. Cast structural elements such as jaws or hammers in crushing machines operate under conditions of an intensive wear. The data indicate that 80% of failures of machines and devices is caused by wearing of rubbing surfaces. This problem became the subject of several scientific and industrial investigations carried out in the whole world in order to produce materials ultra- wear resistant. Methods allowing to obtain wear resistant composite castings are discussed in the hereby paper. Within the performed research microstructures of the produced composite zones were presented and the comparative analysis with regard to mechanical and functional properties of local composite reinforcements in relation to the commercial alloys of increased wear resistance was performed. The results show almost twenty five times increase in wear resistance compared to manganese cast steel containing 18% Mn.

15

Spiekanie tworzyw B4C z dodatkami TiB2, TiC lub TiN

Rutkowski P., Górny G., Góra S.

Materiały Ceramiczne

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2014

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T. 66, nr 2

156--164

PL

Niniejsza praca dotyczy porównania różnych metod spiekania tworzyw z osnową węglika boru. W celu podwyższenia odporności na kruche pękanie do materiału wprowadzano fazy mogące generować naprężenia w materiale ze względu na różnicę współczynników rozszerzalności. Jako fazę dyspergowaną użyto węglik tytanu, azotek tytanu i dwuborek tytanu w ilości do 20% objętościowych. Tworzywa uzyskiwano na drodze spiekania swobodnego, prasowania na gorąco oraz SPS (ang. spark plasma sintering). Określono i poddano analizie ich skład fazowy, mikrostrukturę, zagęszczenie oraz podstawowe właściwości mechaniczne. Na bazie przeprowadzonych badań wykazano, że technika SPS nie nadaje się do spiekania tego typu tworzyw kompozytowych oraz, że najbardziej obiecującym układem jest B4C-TiB2 otrzymywany drogą prasowania na gorąco. Wprowadzenie fazy dwuborku tytanu do osnowy B4C w ilości nie większej niż 15% obj. spowodowało podwyższenie twardości, wytrzymałości na zginanie oraz odporności na kruche pękanie wytworzonych kompozytów w porównaniu z czystymi materiałami B4C.

EN

In the work, different sintering methods of boron carbide based materials were compared. Phases, that lead to generation of thermal stresses, were incorporated to the composites’ matrix to enhance fracture toughness. The stresses can be generated because of a difference in thermal expansion coefficients of constituent phases. Titanium carbide, titanium nitride and titanium diboride were used as the dispersed particles in the boron carbide matrix in quantities up to 20 vol.%. The particulate composites were obtained on the way of pressureless sintering, hot-pressing and spark plasma sintering. The phase composition, microstructural features, densification and basic mechanical properties were determined for the sintered composite materials, and analyzed. On the base of recorded results it was shown that the SPS technique cannot be applied for sintering of these materials. The B4C-TiB2 hot-pressed composite system manifested to be the most promising one. The incorporation of smaller than 15 vol.% of TiB2 to the B4C matrix caused an increase in hardness, bending strength and fracture toughness of the hot-pressed composites when compared to the pure B4C materials.

16

The influence of boron on the adsorption of Ti and C on TiC surfaces

Fan X., Ding H., Chu K

Materials Science Poland

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2014

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Vol. 32, No. 1

112--120

EN

The first-principles calculations have been performed to study the influence of boron on the adsorption of Ti and C on different TiC surfaces. It is found that boron can be adsorbed on both TiC (001) and (111) surfaces. When boron is present and carbon supply is high during the preparation of TiC, boron can bond with carbon atoms to form B–C clusters on (001) surface, but the formation of them is less favorable than that of Ti–C clusters. However, under the low carbon-supply condition, both B–B and Ti–Ti clusters can be formed, and, once being formed, B–B clusters are more stable than the Ti–Ti ones. On Ti-terminated (111) surfaces, boron adatoms are more likely to be moved to form B–B clusters. The study of the diffusion of the adatoms on the surfaces demonstrates that boron adatoms can be more easily migrated on (111) surfaces, which further confirms the above results.

17

Effects of different Sn contents on formation of Ti2SnC by self-propagating high-temperature synthesis method in Ti-Sn-C and Ti-Sn-C-TiC systems

Sun H Y, Kong X, Sen W, Yi Z Z, Wang B S, Liu G Y

Materials Science Poland

|

2014

|

Vol. 32, No. 4

696--701

EN

Effect of different Sn contents on combustion synthesis of Ti2SnC was studied using elemental Ti, Sn, C and TiC powders as raw materials in the Ti–Sn–C and Ti–Sn–C–TiC system, in which the molar ratio of Ti/C was set as 2:1. The reaction mechanism for the formation of Ti2SnC was also investigated. The results showed that the amount of Ti2SnC in combustion products firstly increased with increasing of Sn content (0.6 to 0.8 mol), and then decreased with further increasing of Sn content (1.0 to 1.2 mol). Upon addition of 15 % TiC instead of Ti and C, the optimum addition of Sn decreased to 0.7 mol and a higher purity of Ti2SnC was obtained. The Ti2SnC powders were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD).

18

Composite zones produced in iron castings by in-situ synthesis of TiC carbides

Olejnik E., Górny M., Tokarski T., Grabowska B., Kmita A., Sikora G.

Archives of Metallurgy and Materials

|

2013

|

Vol. 58, iss. 2

465--471

EN

The study discusses a method of producing composite zones at the edge of castings made of ferritic-pearlitic ductile iron. Composite zones were produced in castings made of ferritic-pearlitic ductile iron at the casting edge. The reinforcing phase for the composite zone was TiC carbide, obtained by in-situ synthesis of substrates introduced into the mould in the form of compacts. The composition of the substrates of the reaction of the TiC synthesis was next enriched with an Fe filler added in an amount of 10 and 50 wt. % to investigate the possibility of changing the hardness of the composite zone. The addition of filler changed the surface fraction and the average size of TiC precipitates. In the case of the 50 wt. % addition, a tenfold reduction in the dimensions of the carbides was obtained. This increased their surface fraction relative to the compact composition containing only 10 wt. % of the filler. Changes in mechanical properties were analysed within the zone area by the measurement of hardness HV. The study showed a gradual decrease of the zone hardness in function of the amount of the filler added. This trend was also true as regards the composite zone in castings, where a significant refinement and increased surface content of the TiC precipitates was observed.

PL

W pracy omówiono metodę wytwarzania stref kompozytowych w odlewach z ferrytyczno-perlitycznego żeliwa sferoidalnego. Faza wzmacniająca strefy kompozytowej był węglik tytanu (TiC), uzyskany w wyniku syntezy in situ substratów wprowadzonych do formy w postaci wyprasek. Do kompozycji substratów reakcji syntezy TiC wprowadzono wypełniacz, proszek Fe w ilości 10 i 50 %mas. w celu zbadania możliwości zmiany twardości strefy kompozytowej. Dodatek wypełniacza spowodował zmiane udziału powierzchniowego oraz średniej wielkości TiC. W przypadku 50 %mas. dodatku wypełniacza otrzymano dziesięciokrotne zmniejszenie wymiarów węglików. Analizowano zmiany mechaniczne w obrębie strefy, badając jej twardość HV. Badana wykazały stopniowy spadek twardości strefy wraz z ilością dodawanego wypełniacza. Tendencja ta dotyczyła również strefy kompozytowej odlewu, w którym stwierdzono znaczne rozdrobnienie wydzieleń TiC i wzrost ich udziału powierzchniowego.

19

Composite zones obtained by in situ synthesis in steel castings

Olejnik E., Sobula S., Tokarski T., Sikora G.

Archives of Metallurgy and Materials

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2013

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Vol. 58, iss. 3

769--773

EN

Application of in-situ technique allows for fabrication of composite zone in the casting with a matrix of cast steel with low carbon content. The reinforcing phase in the composite zone is titanium carbide, produced by the synthesis of substrates introduced into the mould in the form of pressed compacts. Metallographic studies were performed in order to determine of homogeneity of composite zones and characteristic features existed in transition area between the composite zone and core of the casting. The transition areas of composites zone were blurred and there were no discontinuities caused by poor bonding between the composite zone and the core of the casting. To confirm the correct run of the TiC synthesis, phase analysis was performed of the base alloy as well as composite zone. The results of this examination indicated that there were two phases in composite zone, i.e. α Fe and TiC and only α Fe was observed in base alloy. Changes of mechanical properties in the composite zone were examined, measuring its hardness HV. The average hardness values of the base alloy and composite zone were 175±4 and 696±201 HV, respectively.

PL

W odlewie z ferrytycznego staliwa o niskiej zawartosci węgla, otrzymano strefy kompozytowe. Fazą wzmacniającą strefy kompozytowej był węglik tytanu TiC, uzyskany w wyniku syntezy in situ substratów, wprowadzonych do formy w postaci wyprasek. Przeprowadzono badania metalograficzne stref kompozytowych w celu określenia jednorodności otrzymanej strefy kompozytowej oraz charakteru obszaru przejściowego: strefa kompozytowa - rdzeń odlewu. Obszar przejściowy, pomiędzy strefa kompozytowa, a rdzeniem odlewu, charakteryzował się gradientowym rozkładem TiC oraz brakiem nieciągłości. W celu potwierdzenia prawidłowego przebiegu procesu syntezy TiC, przeprowadzono analizę fazową stopu bazowego oraz otrzymanej strefy kompozytowej. Potwierdzono, że w obrębie strefy kompozytowej występują dwie fazy tj. α Fe i TiC, a stop bazowy zawiera wyłącznie α Fe. Analizowano zmiany mechaniczne w obrębie otrzymanej strefy kompozytowej, badając jej twardość HV. Średnia wartość twardości stopu bazowego oraz strefy kompozytowej wynosiła odpowiednio 175±4 i 696±201 HV.

20

Analysis of the structure and abrasive wear resistance of white cast iron with precipitates of carbides

Kopyciński D., Kawalec M., Szczęsny A., Gilewski R., Piasny S.

Archives of Metallurgy and Materials

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2013

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Vol. 58, iss. 3

973--976

EN

The resistance of castings to abrasive wear depends on the cast iron abrasive hardness ratio. It has been anticipated that the white cast iron structure will be changed by changing the type of metal matrix and the type of carbides present in this matrix, which will greatly expand the application area of castings under the harsh operating conditions of abrasive wear. Detailed metallographic analysis was carried out to see the structure obtained in selected types of white cast iron, i.e. with additions of chromium and vanadium. The study compares the results of abrasive wear resistance tests performed on the examined types of cast iron.

PL

Odporność żeliwa na zużycie ścierne zależy od stosunku twardości metalu i ścierniwa. W pracy założono kształtowanie struktury żeliwa białego w wyniku zmiany rodzaju osnowy metalowej oraz węglików, co znacznie rozszerza obszar zastosowania odlewu w trudnych warunkach zużycia ściernego. Przeprowadzono szczegółowa analizę metalograficzną struktury wybranych gatunków żeliwa białego t.j.: chromowego oraz wanadowego. W niektórych przypadkach zaproponowano koncepcje sterowania ilością i rodzajem węglików w osnowie metalowej żeliwa lub wprowadzania dodatkowych węglików do struktury eutektycznej tego rodzaju żeliwa. Ponadto w pracy porównano wyniki badań odporności na zużycie ścierne analizowanych gatunków żeliwa.