Submitted work deals with the analysis of reoxidation processes for aluminium alloys. Due to the aluminium high affinity to the oxygen, the oxidation and consequently reoxidation will occur. Paper focuses on the gating system design in order to suppress and minimize reoxidation processes. Design of the gating system is considered as one of the most important aspect, which can reduce the presence of reoxidation products - bifilms. The main reason for the reoxidation occurrence is turbulence during filling of the mold. By correctly designing the individual parts of gating system, it is possible to minimize turbulence and to ensure a smooth process of the mold filling. The aim of the work is an innovative approach in the construction of gating system by using unconventional elements, such as a naturally pressurized system or vortex elements. The aim is also to clarify the phenomenon during the gating system filling by visualization with the aid of ProCAST numerical simulation software. ProCAST can calculate different indicators which allow to better quantify the filling pattern.

Main aim of submitted work is evaluation and experimental verification of inoculation effect on Al alloys hot-tear sensitivity. Submitted work consists of two parts. The first part introduces the reader to the hot tearing in general and provides theoretical analysis of hot tearing phenomenon. The second part describes strontium effect on hot tearing susceptibility, and gives the results on hot tearing for various aluminium alloys. During the test, the effect of alloy chemical composition on hot tearing susceptibility was also analyzed. Two different Al-based alloys were examined. Conclusions deals with effect of strontium on hot tearing susceptibility and confirms that main objective was achieved.

The presented work discusses the influence of material of foundry mould on the effect of modification of AlSi11 alloy. For this purpose castings were produced in moulds made of four various materials. Castings of the first type were cast in a metal die, the second ones in the conventional mould of bentonite-bound sand, those of the third type in the sand mould with oil binder, the last ones in a shell mould where phenol-formaldehyde resin was applied as a binder. All the castings were made of AlSi11 alloy modified with strontium. For a purpose of comparison also castings made of the non-modified alloy were produced. The castings were examined with regard to their microstructures. The performed investigations point out that the addition of strontium master alloy results in refining of the alloy structure, particularly of the α-phase, causes some morphological changes in the alloy and the refinement of eutectics. The advantageous influence of modifier on the structure of the examined silumin was observed particularly in the case of alloy cast either in the conventional oil-bound sand mould or in the shell mould. The non-modified alloy cast into a metal die exhibits a structure similar to those of modified alloy solidifying in the other moulds. The improvement in both tensile strength and unit elongation suggests that the modification was carried out correctly. The best mechanical properties were found for the alloy cast in a metal die, both with and without modification treatment.

This paper presents a study of the effect of the modification and cooling rate on the grain count α(Al) in the Al-5Cu alloy. Research was

performed on castings with walls thickness between 3 mm and 25 mm. Cooling curves were recorded to determine the cooling rate and the

degree of undercooling at the beginning of solidification. It has been shown that cooling rate increases exponentially as the wall thickness

of casting decreases. Moreover it has been demonstrated that the cooling rate of castings changes within a wide range (21ºC/s - 1ºC/s)

when the wall thickness changes from 3 up to 25 mm. Metallographic examinations revealed primary grains (primary α(Al) grains). The

paper show that the relationship between the grain count and the degree of undercooling (for non-modified and modified alloys) can be

represented by the equation N = Nv = np·exp(-b/ΔTα), based on the Weibull's distribution of the size of nucleation sites.

The results of examinations of the influence of titanium-boron inoculant on the solidification, the microstructure, and the mechanical

properties of AlZn20 alloy are presented. The examinations were carried out for specimens cast both of the non-modified and the

inoculated alloy. There were assessed changes in the alloy overcooling during the first stage of solidification due to the nuclei-forming

influence of the inoculant. The results of quantitative metallographic measurements concerning the refinement of the grain structure of

casting produced in sand moulds are presented. The cooling rate sensitivity of the alloy was proved by revealing changes in morphology of

the α-phase primary crystals. Differences in mechanical properties resulting from the applied casting method and optional inoculation were

evaluated.

Pouring of liquid aluminium is typically accompanied by disturbance of the free surface. During these disturbances, the free surface oxide

films can be entrained in the bulk of liquid, also pockets of air can be accidentally trapped in this oxide films. The resultant scattering of

porosity in castings seems nearly always to originate from the pockets of entrained air in oxide films. Latest version of ProCast software

allows to identify the amount of oxides formed at the free surface and where they are most likely to end-up in casts. During a filling

calculation, ProCast can calculate different indicators which allow to better quantify the filling pattern. The fluid front tracking indicator “

Free surface time exposure” has the units [cm2*s]. At each point of the free surface, the free surface area is multiplied by the time. This

value is cumulated with the value of the previous timestep. In addition, this value is transported with the free surface and with the fluid

flow.Experiments to validate this new functions were executed.

This paper deals with the evaluation of the corrosion resistance of the Al-Si alloys alloyed with the different amount of antimony.

Specifically it goes about the alloy AlSi7Mg0,3 which is antimony alloyed in the concentrations 0; 0,001; 0,005; 0,01 a 0,05 wt. % of

antimony. The introduction of the paper is dedicated to the theory of the aluminium alloys corrosion resistance, testing and evaluation of

the corrosion resistance. The influence of the antimony to the Al-Si alloys properties is described further in the introduction. The

experimental part describes the experimental samples which were prepared for the experiment and further they were exposed to the

loading in the atmospheric conditions for a period of the 3 months. The experimental samples were evaluated macroscopically and

microscopically. The results of the experiment were documented and the conclusions in terms of the antimony impact to the corrosion

resistance of the Al-Si alloy were concluded. There was compared the corrosion resistance of the Al-Si alloy antimony alloyed (with the

different antimony content) with the results of the Al-Si alloy without the alloying after the corrosion load in the atmospheric conditions in

the experiment.

At thermal junctions of aluminium alloy castings and at points where risering proves to be difficult there appear internal or external

shrinkages, which are both functionally and aesthetically inadmissible. Applying the Probat Fluss Mikro 100 agent, which is based on

nano-oxides of aluminium, results in the appearance of a large amount of fine microscopic pores, which compensate for the shrinking of

metal. Experimental tests with gravity die casting of AlSi8Cu3 and AlSi10Mg alloys have confirmed that the effect of the agent can be of

advantage in foundry practice, leading to the production of castings without local concentrations of defects and without the appearance of

shrinkages and macroscopic gas pores. Also, beneficial effect on the mechanical properties of the metal has been observed.

The paper presents research on the effects of soft annealing parameters on a change of the impact strength KC and Brinell hardness (HB)

of the EN AC-AlSi11 alloy. The research has been performed according to the trivalent testing plan for two input parameters –

temperature in the range between 280°C and 370°C and time in the range between 2 and 8 hours. The application of such heat treatment

improves the plasticity of the investigated alloy. The improvement of the impact strength KC by 71% and the decrease of the hardness HB

by 20% was achieved for the soft annealing treatment conducted at a temperature 370°C for 8 hours, compared to the alloy without the

heat treatment. A change of the form of eutectic silicon precipitations which underwent refinement, coagulation and partial rounding, had

a direct effect on the hardness HB and impact strength KC. The results obtained were used to prepare space plots enabling the temperature

and time for soft annealing treatment to be selected with reference to the obtained impact strength KC and hardness HB of the alloy with

the heat treatment.

Twist extrusion is a processing method involving the extrusion of a sample with a prismatic cross-section using a tool composed of four prismatic parts bisected by a screw component. A beneficial change in mechanical durability is one of the main factors enabling the use of highly durable Al-Mg-Mn-Sc-Zr alloys to construct functional components of non-stationary robots. As part of the present research, ANSYS® software was used to simulate a twist extrusion process. An analysis of a sample entering and passing through the entire twisting area was performed, up to the point of full twisting of the base of the sample. The stress conditions in the sample were analysed as it passed through the twisting area. The highest stress values (reaching up to 600 MPa) were detected at the tips of the sample face as the sample exited the twisting area. The lowest stress values, at around 170 MPa, were detected at the side edges of the sample.

Presented in this paper are results of an experimental investigation on the rivet flexibility and load transmission in a riveted lap joint representative for the aircraft fuselage. The test specimens consisted of two aluminium alloy Alclad sheets joined with 3 rows of rivets. Two different squeeze forces were applied to install the rivets. Rivet flexibility measurements have been performed under constant amplitude fatigue loading using several methods including two original optical techniques developed by the present authors. The axial tractions in the sheets required to determine the rivet flexibility have been derived from strain gauge measurements. In order to eliminate the effect of secondary bending the strain gauges have been bonded at the same locations on the outside and faying surface of the sheet. The experiments enabled an evaluation of the usefulness of various techniques to determine the rivet flexibility. It was observed that, although the measured flexibility was identical for both end rivet rows, the load transfer through either of these rows was different. Previous experimental results by the present authors suggest that behind the non-symmetrical load transfer distribution through the joint are large differences between the rivet hole expansion in the sheet adjacent to the driven rivet head and the sheet under the manufactured head [1]. It has been concluded that commonly used computation procedures according to which the load transfer is only related to the rivet flexibility may lead to erroneous results.