Plasma sprayed ceramic coatings serve as protective layers and are frequently exposed to aggressive wear, corrosion, or high-temperature environment. Currently, alumina and alumina-titania are some of the most popular protective ceramic composite coatings used in the industry. The present work deals with the investigation of the influence of TiO₂ content in the feedstock powder on the resulting microstructure and properties of Al₂O₃, Al₂O₃ + 3 wt% TiO₂, Al₂O₃ + 13 wt% TiO₂ and Al₂O₃ + 40 wt% TiO₂ coatings developed via atmospheric plasma spraying (APS). Specifically, the phase composition, morphology, and microstructure, as well as the mechanical and tribological performance of the coatings were examined. Results revealed that higher content of TiO₂ induced the transformation of phases, leading to the formation of intermediary Al₂TiO₅ and Al₂- xTi₁- xO₅ phases. Also, the dominant α–Al₂O₃ to γ–Al₂O₃ transformation confirmed the formulation of well-melted lamellas within the coating structure. It was also shown that the increase in TiO₂ content decreased the micro-hardness of the coatings due to the formation of the intermediary phases as mentioned above and thus, affected their tribological performance. The lowest volumetric wear, equal to 7.2×10⁻⁵ mm³/(N ∙ m), was reported for Al₂O₃ + 13 wt% TiO₂ coating.

This article deals with the fatigue properties of newly used AlZn10Si8Mg aluminium alloy where the main aim was to determine the

fatigue strength and compare it with the fatigue strength of AlSi7Mg0.3 secondary aluminium alloys which is used in the automotive

industry for cyclically loaded components. AlZn10Si8Mg aluminium alloy, also called UNIFONT 90, is self-hardening (without heat

treatments), which contributes to economic efficiency. This is one of the main reasons why is compared, and may be an alternative

replacement for AlSi7Mg0.3 alloy which is heat treated to achieve required mechanical properties. The experiment results show that the

fatigue properties of AlZn10Si8Mg alloy are comparable, if not better, than AlSi7Mg0.3 alloy. Fatigue properties of AlZn10Si8Mg alloy

are achieved after seven days of natural ageing, immediately after casting and achieving value of fatigue strength is caused by structural

components formed during solidification of the melt.

The aim of this paper was to determine the effect of heat treatment for the corrosion resistance of the ZnAl40Ti2Cu alloy under “acid rain” conditions. ZnAl40TiCu alloy after supersaturation and after supersaturation and aging was studied. Potentiodynamic studies, potentiostatic studies and studies on structure of the alloy top layer of samples after corrosion tests were carried out. These investigations indicated a significant influence of heat treatment on corrosion resistance of the ZnAl40Ti2Cu alloy. The highest increase in corrosion resistance comparing to the alloy in the as-cast condition may be obtained by supersaturation. A significant influence of the aging temperature and time on corrosion resistance was proved.

Secondary or multiple remelted alloys are common materials used in foundries. For secondary (recycled) Al-Si-Cu alloys, the major problem is the increased iron presence. Iron is the most common impurity and with presence of other elements in alloy creates the intermetallic compounds, which may negatively affect the structure. The paper deals with effect of multiple remelting on the microstructure of the AlS9iCu3 alloy with increased iron content to about 1.4 wt. %. The evaluation of the microstructure is focused on the morphology of iron-base intermetallic phases in caste state, after the heat treatment (T5) and after natural aging. The occurrence of the sludge phases was also observed. From the obtained results can be concluded that the multiple remelting leads to change of chemical composition, changes in the final microstructure and also increases sludge phases formation. The use of heat treatment T5 led to a positive change of microstructure, while the effect of natural aging is beneficial only to the 3rd remelting.

The paper deals with problems related to application of aluminum-silicon alloys for combustion engine cylinder liners

The main reason of a cavitational destruction is the mechanical action of cavitation pulses onto the material’s surface. The course

of cavitation destruction process is very complex and depends on the physicochemical and structural features of a material. A resistance

to cavitation destruction of the material increases with the increase of its mechanical strength, fatigue resistance as well as hardness.

Nevertheless, the effect of structural features on the material’s cavitational resistance has been not fully clarified. In the present paper,

the cavitation destruction of ZnAl4 as cast alloy was investigated on three laboratory stands: vibration, jet-impact and flow stands.

The destruction mechanism of ZnAl4 as cast alloy subjected to cavitational erosion using various laboratory stands is shown in the present

paper.

The high mechanical properties of the Al-Li-X alloys contribute to their increasingly broad application in aeronautics, as an alternative forthe aluminium alloys, which have been used so far. The aluminium-lithium alloys have a lower specific gravity, a higher nucleation andcrack spread resistance, a higher Young’s module and they characterize in a high crack resistance at lower temperatures. The aim of theresearch planned in this work was to design an aluminium alloy with a content of lithium and other alloy elements. The research includedthe creation of a laboratorial melt, the microstructure analysis with the use of light microscopy, the application of X-ray methods to identify the phases existing in the alloy, and the microhardness test.

An understanding of the fundamental correlation between grain size and material damping is crucial for the successful development of structural components offering high strength and good mechanical energy absorption. With this regard, we fabricated aluminum sheets with grain sizes ranging from tens of microns down to 60 nm and investigated their tensile properties and mechanical damping behavior. An obvious transition of the damping mechanism was observed at nanoscale grain sizes, and the underlying causes by grain boundaries were interpreted.

Manganese is an effective element used for the modification of needle intermetallic phases in Al-Si alloy. These particles seriously

degrade mechanical characteristics of the alloy and promote the formation of porosity. By adding manganese the particles are being

excluded in more compact shape of “Chinese script” or skeletal form, which are less initiative to cracks as Al5FeSi phase. In the present

article, AlSi7Mg0.3 aluminium foundry alloy with several manganese content were studied. The alloy was controlled pollution for achieve

higher iron content (about 0.7 wt. % Fe). The manganese were added in amount of 0.2 wt. %, 0.6 wt. %, 1.0 wt. % and 1.4 wt. %. The

influence of the alloying element on the process of crystallization of intermetallic phases were compared to microstructural observations.

The results indicate that increasing manganese content (> 0.2 wt. % Mn) lead to increase the temperature of solidification iron rich phase

(TAl5FeSi) and reduction this particles. The temperature of nucleation Al-Si eutectic increase with higher manganese content also. At

adding 1.4 wt. % Mn grain refinement and skeleton particles were observed.

This paper deals with influence on segregation of iron based phases on the secondary alloy AlSi7Mg0.3 microstructure by chrome. Iron is

the most common and harmful impurity in aluminum casting alloys and has long been associated with an increase of casting defects. In

generally, iron is associated with the formation of Fe-rich phases. It is impossible to remove iron from melt by standard operations, but it is

possible to eliminate its negative influence by addition some other elements that affect the segregation of intermetallics in less harmful

type. Realization of experiments and results of analysis show new view on solubility of iron based phases during melt preparation with

higher iron content and influence of chrome as iron corrector of iron based phases. By experimental work were used three different

amounts of AlCr20 master alloy a three different temperature of chill mold. Our experimental work confirmed that chrome can be used as

an iron corrector in Al-Si alloy, due to the change of intermetallic phases and shortening their length.

Al-enriched layer was formed on a magnesium substrate with use of casting. The magnesium melt was cast into a steel mould with an

aluminium insert placed inside. Different conditions of the casting process were applied. The reaction between the molten magnesium and

the aluminium piece during casting led to the formation of an Al-enriched surface layer on the magnesium substrate. The thickness of the

layer was dependent on the casting conditions. In all fabricated layers the following phases were detected: a solid solution of Mg in Al,

Al3Mg2, Mg17Al12 and a solid solution of Mg in Al. When the temperature of the melt and the mould was lower (variant 1 – 670o

C and 310 o

; variant 2 – 680o

C and 310o

C, respectively) the unreacted thin layer of aluminium was observed in the outer zone. Applying higher

temperatures of the melt (685o

C) and the mould (325o

C) resulted in deep penetration of aluminium into the magnesium substrate. Areas

enriched in aluminium were locally observed. The Al-enriched layers composed mainly of Mg-Al intermetallic phases have hardness from

187-256 HV0.1.

In this work, the effect of the microstructure on corrosion behavior of selected Mg- and Al-based as cast alloys, was evaluated. The electrochemical examinations were carried out, and then a morphology of corrosion products formed due to local polarization on materials surface, was analyzed. It was documented that the presence of Mg2Si phase plays an important role in the corrosion course of Mg-based alloy. A selective etching was observed in sites of Mg2Si precipitates having “Chinese script”- like morphology. Analogous situation was found for Al-based alloy, where the key role was played by cathodic θ-CuAl2 phase.

Iron is presented as an impurity in Al-Si alloys and occurs in the form of the β-Al5FeSi phase formations. The presence of iron and other elements in the alloy causes the formation of large intermetallic phases. Due to the high brittleness of this phase, it reduces the mechanical properties and increases the porosity. Manganese is used to inhibit the formation of this detrimental phase. It changes the morphology of the phase to polyhedral crystals, skeletal formations, or Chinese script. The present article deals with the influence of various amounts of manganese (0.1; 0.2; 0.4; 0.6 wt. %) on the formation of iron-based intermetallic phases in the AlSi7Mg0.3 alloy with different levels of iron content (0.4; 0.8, 1.2 wt. %). The increase of iron content in each alloy caused the creation of more intermetallic compounds and this effect has been more significant with higher concentrations of manganese. In alloys where the amount of 1.2 wt. % iron is present, the shape of eutectic silicon grain changes from angular to short needle type.

Metal alloys with matrix based on an Fe-Al system are generally considered materials for high-temperature applications. Their main advantages are compact crystallographic structure, long-range ordering and structural stability at high temperatures. These materials are based on an intermetallic phase of FeAl or Fe3Al, which is stable in the range from room temperature up to the melting point of 1240°C. Their application at high temperatures is also beneficial because of the low cost of production, very good resistance to oxidation and corrosion, and high mechanical strength. The casting alloy the structure of which includes the FeAl phase is, among others, highaluminium cast iron. This study has been devoted to the determination of the effect of vanadium and titanium on the transformation of the high-aluminium cast iron structure into an in-situ FeAl-VC composite.

The present research was conducted on thin-walled castings with 5 mm wall thicknesses. This study addresses the effect of the influence of

different master alloys, namely: (1) Al-5%Ti-1%B, (2) Al-5%Ti and (3) Al-3%B, respectively on the structure and the degree of

undercooling (ΔTα = Tα-Tmin, where Tα - the equilibrium solidification temperature, Tmin - the minimum temperature at the beginning of

α(Al) solidification) of an Al-Cu alloy. The process of fading has been investigated at different times spent on the refinement treatment ie.

from 3, 20, 45 and 90 minutes respectively, from the dissolution of master alloys. A thermal analysis was performed (using a type-S

thermocouple) to determine cooling curves. The degree of undercooling and recalescence were determined from cooling and solidification

curves, whereas macrostructure characteristics were conducted based on a metallographic examination. The fading effect of the refinement

of the primary structure is accompanied by a significant change in the number (dimension) of primary grains, which is strongly correlated

to solidification parameters, determined by thermal analysis. In addition to that, the analysis of grain refinement stability has been shown

with relation to different grain refinements and initial titanium concentration in Al-Cu base alloy. Finally, it has been shown that the

refinement process of the primary structure is unstable and requires strict metallurgical control.

This study presents an analysis of aluminium cast iron structure (as-cast condition) which are used in high temperatures. While producing casts of aluminium iron, the major influence has been to preserve the structure of the technological process parameters. The addition of V, Ti, Cr to an Fe-C-Al alloy leads to the improvement of functional and mechanical cast qualities. In this study, a method was investigated to eliminate the presence of undesirable Al4C3 phases in an aluminium cast iron structure and thereby improve the production process. V and Ti additions to aluminium cast iron allow the development of FeAl - VC or TiC alloys. In particular, V or Ti contents above 5 wt.% were found to totally eliminate the presence of Al4C3. In addition, preliminary work indicates that the alloy with the FeAl - VC or TiC structure reveals high oxidation resistance. The introduction of 5 wt.% chromium to aluminium cast iron strengthened the Al4C3 precipitate. Thus, the resultant alloy can be considered an intermetallic FeAl matrix strengthened by VC and TiC or modified Al4C3 reinforcements.

The paper deals with the influence of manganese in AlSi7Mg0.3 alloy with higher iron content. Main aim is to eliminate harmful effect of intermetallic – iron based phases. Manganese in an alloy having an iron content of about 0.7 wt. % was graded at levels from 0.3 to 1.4 wt. %. In the paper, the effect of manganese is evaluated with respect to the resulting mechanical properties, also after the heat treatment (T6). Morphology of the excluded intermetallic phases and the character of the crystallisation of the alloy was also evaluated. From the obtained results it can be concluded that the increasing level of manganese in the alloy leads to an increase in the temperature of the β-Al5FeSi phase formation and therefore its elimination. Reducing the amount of β-Al5FeSi phase in the structure results in an improvement of the mechanical properties (observed at levels of 0.3 to 0.8 wt. % Mn). The highest addition of Mn (1.4 wt.%) leads to a decrease in the temperature corresponding to the formation of eutectic silicon, which has a positive influence on the structure, but at the same time the negative sludge particles were also present

The paper deals with squeeze casting technology. For this research a direct squeeze casting method has been chosen. The influence of process parameters variation (casting temperature, mold temperature, pressure) on mechanical properties and structure will be observed. The thicknesses of the individual walls were selected based on the use of preferred numbers and series of preferred numbers (STN ISO 17) with the sequence of 3.15, 4.00, 5.00, 6.00 and 8.00 mm. The width of each wall was 22 mm with a length of 100 mm. As an experimental material was chosen the AlSi12 and AlSi7Mg0.3 alloys. The mechanical properties (UTS, E) for individual casting parameters and their individual areas of different thicknesses were evaluated. In the structure the influence of pressure on the change of the eutectic morphology, the change of the volume of eutectic and the primary alpha phase, the effect of the pressure on the more fine-grain and the regularization of the structure were evaluated.

Thermal analysis allows for determination of temperature specific for the beginning and the end of phase transitions occurring in studied samples. In this paper results obtained from DTA (Differential Thermal Analysis) of alloys of chemical composition referring to nickel-rich part of Ni-Al-Cr system, specifically from section Ni75Al25÷Ni65Cr35 are presented. Those alloys are based on intermetallic phase Ni3Al. Referring to measurements obtained during heating and cooling, characteristic peaks related to occurrence of phase transition of order-disorder type were noted as well as melting and solidification temperature of alloys was determined. Results of thermal analysis DTA of studied range were compared with results obtained for section Ni75Al25÷Ni75Cr25 and Ni75Al25÷Ni87Cr13, additionally results of measurements performed on high-temperature solution calorimeter were collated. Both methods presented good compatibility.

In this study, metal matrix composite materials containing melt-spun Al-20Si-5Fe alloys and boron carbide was produced by high energy ball milling and then hot pressing at 200 MPa pressure and 450°C. Mechanical and microstructural characterizations were performed by using an optical microscopy, X-Ray diffractometer, and dynamic microhardness tester. It was observed that boron carbide particles were homogenously distributed in the microstructure and values of microhardness and elastic modules were averagely 830 MPa and 42 GPa, respectively.

A series of Al-5Ti-1B master alloys were obtained via fluoride salt process by holding them between 780°C and 880°C for 10-90 min. The influence of holding temperature and time during preparation on the microstructure and its refining performance were investigated by X-ray diffractometer, optical microscopy and scanning electron microscopy equ ipped with energy dispersive X-ray spectroscopy. The results indicated both the morphology and the distribution of TiB2 and Al3Ti were seriously affected by holding conditions. Inadequate TiB2 particles were generated when holding time was short. However, Fe-containing impurity particles that aggregated along the matrix grain boundaries were found after the prolonged holding time. The refining and microhardness test results revealed that Al -5Ti-1B, the one held at 820°C for 30 min showed the optimum refining efficiency on Al-Cu alloy.

This paper focused on the effect of pure torsion deformation and various torsion pitches on the mechanical properties of the commercial pure Al wires which has not been examined so far. The initial wires with diameter of 4 mm have been torsion deformed to different pitch length (PL). In order to investigate the effect of gradient microstructure caused by torsion deformation, three different pitch length of 15 mm, 20 mm and 30 mm are considered. The results revealed that the level of grain refinement is correlated with the amount of induced plastic shear strain by torsion deformation. For the wire with pitch length of 15 mm, the grain sizes decreased to about 106 μm and 47 μm in the wire center and edge from the initial size of about 150 μm of the annealed wire. The micro-hardness measurement results show a gradient distribution of hardness from the wire center to the wire surface that confirmed the increasing trend of plastic shear strain obtained by FE simulations. The hardness of annealed sample (35 HV) is increased up to 73 HV at the wire surface for the smallest pitch length. The yield and ultimate tensile strength of the torsion deformed wires are also increased up to about 85 MPa and 152 MPa from the initial values of 38 MPa and 103 MPa of the annealed one respectively while the maximum elongation reduced significantly.

The paper presents the results of research studies involving the ceramic-metal tool materials with the deposited nitride coatings on the basis of aluminium, titanium and silicon. The cathodic arc evaporation with lateral rotating cathodes method was used for deposition of nanocrystalline, wear resistant nitride coatings – AlTiSiN type. Structural examinations are presented of the applied coatings and their support material made on the scanning electron microscope (SEM) and the scanning/transmission electron microscope (STEM). Chemical composition analysis as a function of the distance from the specimen surface, the so-called profile analysis, were carried out also. The structural analysis confirms that deposited multilayer coatings have dense microstructure without any visible porosity and delamination. It was found that the investigated coatings have nanocrystalline structure and consisting of fine crystallites even less than 6nm. Lattice deformations and numerous structural defects were also observed in the nanolayers. Depositing the AlTiSiN coatings results in the significant hardness increase within the range of 2252 ±256 to 2908 ±295 HV0.01.