With the increase in wall thickness of the casting of iron-nickel-aluminium-bronze, by the reduction of the cooling rate the size of κII phase

precipitates increases. This process, in the case of complex aluminium bronzes with additions of Cr, Mo and W is increased. Crystallization

of big κII phase, during slow cooling of the casting, reduces the concentration of additives introduced to the bronze matrix and hardness.

Undertaken research to develop technology of thick-walled products (g> 6 mm) of complex aluminium bronzes. Particular attention

was paid to the metallurgy of granules. As a result, a large cooling speed of the alloy, and also high-speed solidification casting a light

weight of the granules allows: to avoid micro-and macrosegregation, decreasing the particle size, increase the dispersion of phases in

multiphase alloys. Depending on the size granules as possible is to provide finished products with a wall thickness greater than 6 mm by

infiltration of liquid alloy of granules (composites). Preliminary studies was conducted using drip method granulate of CuAl10Fe5Ni5

bronze melted in a INDUTHERM-VC 500 D Vacuum Pressure Casting Machine. This bronze is a starting alloy for the preparation of the

complex aluminium bronzes with additions of Cr, Mo, W and C or Si. Optimizations of granulation process was carried out. As the process

control parameters taken a casting temperature t (°C) and the path h (mm) of free-fall of the metal droplets in the surrounding atmosphere

before it is intensively cooled in a container of water. The granulate was subjected to a sieve analysis. For the objective function was

assume maximize of the product of Um*n, the percentage weight "Um" and the quantity of granules 'n' in the mesh fraction. The maximum

value of the ratio obtained for mesh fraction a sieve with a mesh aperture of 6.3 mm. In the intensively cooled granule of bronze was

identified microstructure composed of phases: β and fine bainite (α+β'+β'1) and a small quantity of small precipitates κII phase. Get high

microhardness bronze at the level of 323±27,9 HV0,1.

According to the analysis of the current state of the knowledge shows that there is little information on the process of phase transformations

that occur during the cooling Cu-Al-Fe-Ni hypo-eutectoid bronzes with additions of Cr, Mo and/or W, made additions individually

or together, for the determination of: the type of crystallizing phases, crystallizing phases, order and place of their nucleation.

On the basis of recorded using thermal and derivative analysis of thermal effects phases crystallization or their systems, analysis of the

microstructure formed during crystallization - observed on the metallographic specimen casting ATD10-PŁ probe, analysis of the existing

phase equilibrium diagrams forming elements tested Cu-Al-Fe-Ni bronze, with additions of Cr, Mo, W and/or Si developed an original

model of crystallization and phase transformation in the solid state, the casting of high quality Cu-Al-Fe-Ni bronze comprising: crystallizing

type phase, crystallizing phase sequence, place of nucleation.

Small additions of Cr, Mo and W to aluminium-iron-nickel bronze are mostly located in phases κi (i=II; III; IV),and next in phase α

(in the matrix) and phase γ2. They raise the temperature of the phase transformations in aluminium bronzes as well as the casts’ abrasive

and adhesive wear resistance. The paper presents a selection of feeding elements and thermal treatment times which guarantees structure

stability, for a cast of a massive bush working at an elevated temperature (650–750°C) made by means of the lost foam technology out of

composite aluminium bronze. So far, there have been no analyses of the phenomena characteristic to the examined bronze which

accompany the process of its solidification during gasification of the EPS pattern. There are also no guidelines for designing risers and

steel internal chill for casts made of this bronze. The work identifies the type and location of the existing defects in the mould’s cast. It also

proposes a solution to the manner of its feeding and cooling which compensates the significant volume contraction of bronze and

effectively removes the formed gases from the area of mould solidification. Another important aspect of the performed research was

establishing the duration time of bronze annealing at the temperature of 750°C which guarantees stabilization of the changes in the bronze

microstructure – stabilization of the changes in the bronze HB hardness.

The article presents the investigations of 7xxx aluminium alloys performed by the method of thermal and derivational analysis. The studies made it possible to identify the effect of the changes in the Cu concentration, the total Zn and Mg weight concentrations and the Zn/Mg weight concentration ratio on their crystallization process: the cooling as well as the kinetics and dynamics of the thermal process of cooling and crystallization. Metallographic studies were performed on the microstructure of the examined alloys and their HB hardness was measured. The evaluation of the changes was presented in reference to the model alloys EN AW-7003 and EN AW-7010, whose microstructure under the conditions of thermodynamic equilibrium are described by the phase diagrams: Al-Zn-Mg and Al-Zn-Mg-Cu. The performed investigations confirmed that the hardness HB of the examined alloys is mainly determined by the reinforcement of the matrix αAl by the introduced alloy additions and the presence of phases Θ(Al2Cu) and S(Al2CuMg) rich in copper, as well as η(MgZn2), in the examined alloys' microstructure. The increase of the amount of intermetallic phases precipitated in the microstructure of the examined alloys is caused, beside Cu, by the characteristic change of Zn wt. concentration and Mg. It was proposed that the process of one-stage thermal treatment of the examined alloys be introduced at a temperature of up to tJ-20 °C, which will prevent the exceedance of the solidus temperature.

Metallographic investigations and a computer simulation of stresses in a gravity die-casting bushing were performed. Simulation of the casting process, solidification of the thick-walled bushing and calculations of the stress was performed using MAGMA5.3 software. The size variability of phases κIIaffecting the formation of phase stresses σf, depending on the location of the metallographic test area, was identified. The distribution of thermal σtand shrinkage stresses σs, depending on the location of the control point SC in the bushing's volume, was estimated. Probably the nature of these stresses will change slightly even after machining. This can cause variations in operating characteristics (friction coefficient, wear). Due to the strong inhomogeneity of the stress distribution in the bushing's casting, it is necessary to perform further tests of the possibility to conduct thermal treatment guaranteeing homogenization of the internal stresses in the casting, as well as to introduce changes in the bushing's construction and the casting technology. The paper presents the continuation of the results of research aimed at identifying the causes of defects in the thick-walled bushing, die-casting made of CuAl10Fe5Ni5Cr aluminium bronze.

For the die casting conditions of aluminium bronzes assumed based on the literature data, a thick-walled bush was cast, made of complex

aluminium bronze (Cu-Al-Fe-Ni-Cr). After the cast was removed from the mould, cracks were observed inside it. In order to identify the

stage in the technological production process at which, potentially, the formation of stresses damaging the continuity of the microstructure

created in the cast was possible (hot cracking and/or cold cracking), a computer simulation was performed. The article presents the results

of the computer simulation of the process of casting the material into the gravity die as well as solidifying and cooling of the cast in the

shape of a thick-walled bush. The simulation was performed with the use of the MAGMA5 program and by application of the

CuAl10Ni5,5Fe4,5 alloy from the MAGMA5 program database. The results were compared with the location of the defects identified in

the actual cast. As a result of the simulation of the die-casting process of this bush, potential regions were identified where significant

principal stresses accumulate, which can cause local hot and cold cracking. Until now, no research has been made of die-cast aluminium

bronzes with a Cr addition. Correlating the results of the computer simulation validated by the analysis of the actual cast made it possible

to clearly determine the critical regions in the cast exposed to cracking and point to the causes of its occurrence. Proposals of changes in

the bush die casting process were elaborated, in order to avoid hot tearing and cold cracking. The article discusses the results of

preliminary tests being a prologue to the optimization of the die-casting process parameters of complex aluminium bronze thick-walled

bushs.

The study presents the results of the investigations of the effect of Cu, Ni, Cr, V, Mo and W alloy additions on the microstructure and

mechanical properties of the AlSi7Mg0.3 alloy. The examinations were performed within a project the aim of which is to elaborate an

experimental and industrial technology of producing elements of machines and devices complex in their construction, made of aluminium

alloys by the method of precision investment casting. It was demonstrated that a proper combination of alloy additions causes the

crystallization of complex intermetallic phases in the silumin, shortens the SDAS and improves the strength properties: Rm, Rp0.2,HB

hardness. Elevating these properties reduces At, which, in consequence, lowers the quality index Q of the alloy of the obtained casts.

Experimental casts were made in ceramic moulds preliminarily heated to 160 °C, into which the AlSi7Mg0.3 alloy with the additions was

cast, followed by its cooling at ambient temperature. With the purpose of increasing the value of the quality index Q, it is recommended

that the process of alloy cooling in the ceramic mould be intensified and/or a thermal treatment of the casts be performed (ageing)(T6).

The work presents the results of the investigations of the effect of inhibitors coated on the internal walls of a ceramic mould on the quality

of the obtained casts made of the AM60 alloy containing additions of chromium and vanadium. In order to reduce the reactivity of

magnesium alloy cast by the technology of investment casting with the material of the mould and the ambient atmosphere, solid inhibitors

were applied in the form of a mixture of KBF4 and H3BO3 after the stage of mould baking and before the mould’s being filled with the

liquid alloy. For the purpose of examining the effect of the inhibitors on the surface quality of the obtained casts, profilometric tests were

performed and the basic parameters describing the surface roughness, Ra, Rz and Rm, were determined.

Titanium alloy (Ti-6Al-4V) has been extensively used in aircraft turbine-engine components, aircraft structural components, aerospace fasteners, high performance automotive parts, marine applications, medical devices and sports equipment. However, wide-spread use of this alloy has limits because of difficulty to machine it. One of the major difficulties found during machining is development of poor quality of surface in the form of higher surface roughness. The present investigation has been concentrated on studying the effects of cutting parameters of cutting speed, feed rate and depth of cut on surface roughness of the product during turning of titanium alloy. Box-Behnken experimental design was used to collect data for surface roughness. ANOVA was used to determine the significance of the cutting parameters. The model equation is also formulated to predict surface roughness. Optimal values of cutting parameters were determined through response surface methodology. A 100% desirability level in the turning process for economy was indicated by the optimized model. Also, the predicted values that were obtained through regression equation were found to be in close agreement to the experimental values.

The article presents the investigation results of the crystallization (performed by means of the TDA method) and the microstructure of complex aluminium bronzes with the content of 6% Al, 4% Fe and 4% Ni, as well as Si additions in the scope of 1–2% and Cr additions in the scope of 0.1–0.3%, which have not been simultaneously applied before. For the examined bronze, the following tests were performed: hardness HB, impact strength (KU2). For bronze CuAl6Fe4Ni4Si2Cr0.3, characterizing in the highest hardness, wear tests were conducted with dry friction and the dry friction coefficient. The investigations carried out by means of the X-ray phase analysis demonstrated the following phases in the microstructure of this bronze: αCu, γ2 and complex intermetallic phases based on iron silicide type Fe3Si (M3Si M={Fe,Cr,…}). Compared to the normalized aluminium bronzes (μ=0.18–0.23), the examined bronze characterizes in relatively low wear and lower friction coefficient during dry friction (μ=0.147±0.016).