Abstract This paper presents the results of research on material and microstructural effects in a hypoutectic Al–Mg– Si–Mn–Fe alloy, modified by the addition of Ti and Ti + P, in two series of castings, gravity and pressure. It has been found that the use of high pressure die casting technology allows for significant improvement of mechanical properties, especially tensile strength and plasticity of the examined alloy. On the other hand, the addition of Ti and Ti + P caused different material effects. In gravity castings, the addition of Ti and Ti + P caused a decrease in strength and plasticity, while in high-pressure castings, an increase in the values of these parameters was observed. The microstructural effects related to the foundry technology and those caused by Ti and P additions were revealed, such as differences in the phase composition of the interdendritic eutectics and in the morphology and dispersion of their phase constituents: Mg2Si and α-Al(Fe,Mn)Si.

Together with development of casting technology for Al-Si-Mg alloys, new groups of casting materials are undergoes its implementation into foundry practice. Al-Mg-Si casting alloys possessed several advantages such as good strength in as-cast state combined with high ductility, good corrosion resistance and castability. In both Al-Si-Mg and Al-Mg-Si systems, the range of the eutectic crystallization occurs: L → αAl + βSi and L → αAl + Mg2Si, respectively. In the hypoeutectic alloys of both system as a primary phase – dendrites of the solid solution αAl solidify. The transition elements – Ti, Zr, Sc, which provides efficient grain refinement can dissolve in this solid solution αAl causing precipitation strengthening effect. In the article the present state of the researches on the development of Al-Mg-Si casting alloys is considered together with the results of the examinations on the effect of Ti addition on the microstructure of the AlMg5Si2Mn alloy. These researches results were discussed at the annual conference on the casting of non-ferrous metals “Science and Technology” (2018) and initially presented in an shortened form in the article [1].

The article presents a novel method that allows measurement of thermal conductivity that is based on Stefan-Boltzmann law. The developed method can be used to determine thermal conductivity of ceramic investment casting molds. The methodology for conducting thermal conductivity tests of ceramic material samples is presented. Knowledge of the value of thermal capacity and thermal conductivity as a function of temperature enables computer simulations of the process of cooling and solidification of liquid metal in a mold.

The designing of new light-weight alloys for continuous replacement of cast iron and steel parts is now the mainstream regarding energy saving and improvement of fuel consumption in the transportation sector. Parallel with the remarkable advances in aluminium wrought alloys, the search for novel efficient casting alloys still attracts the attention of researchers and manufacturers of aluminium casting. The last decades have shown a growing interest in Al-Mg-Si-Mn casting alloys. Despite their active implementation into foundry practice, there is a lack of research regarding their structural formation after additional alloying by Cu, Zn, Sc, Zr, Ti, Li, and especially the effect of ‘natural hardening’ when an alloy undergoes aging from as-cast condition. In this paper the authors have summarised the existing information on the Al-Mg-Si-Mn casting alloys, including their structure and the effects of Mn, Cu, Zn, Sc, Sc+Zr and Li additions on the properties, along with their own results concerning this group of casting materials.

The publication presents the comparison of selected refining methods (gaseous and/or flux) based on mechanical properties of the obtained secondary silumin EN AC-AlSi7Mg0.3 (in accordance to the European Standard PN-EN 1706:2011). The point of reference was a similar primary alloy produced using pure batch materials. The mechanical properties measured in room temperature were used to calculate the materials quality index. The research showed, that properly carried out refinement process of secondary (recycled) alloys can bring their quality indexes close to those of their primary materials. The goal was to assess the efficiency of selected refining methods when applied to the examined group of casting silumins, by measuring the basic mechanical properties (in room temperature) before and after refining. The practical aspect was to choose an effective (ecologically, technologically and economically) method of refining of secondary EN AC-AlSi7Mg0.3 alloy used to cast car rims for JN METAL company in Ostowiec Świętokrzyski (Poland).

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.

High prices of tin and its limited resources, as well as several valuable properties characterising Cu-Sn alloys, cause searching for materials of similar or better properties at lower production costs. The influence of various nickel additions to CuSn10 casting bronze and to CuSn8 bronze of a decreased tin content was tested. Investigations comprised melting processes and casting of tin bronzes containing various nickel additions (up to 5%). The applied variable conditions of solidification and cooling of castings (metal and ceramic moulds) allowed to assess these alloys sensitivity in forming macro and microstructures. In order to determine the direction of changes in the analysed Cu-Sn-Ni alloys, the metallographic and strength tests were performed. In addition, the solidification character was analysed on the basis of the thermal analysis tests. The obtained results indicated the influence of nickel in the solidification and cooling ways of the analysed alloys (significantly increased temperatures of the solidification beginning along with increased nickel fractions in Cu-Sn alloys) as well as in the microstructure pattern (clearly visible grain size changes). The hardness and tensile strength values were also changed.It was found, that decreasing of the tin content in the analysed bronzes to which approximately 3% of nickel was added, was possible, while maintaining the same ultimate tensile strength (UTS) and hardness (HB) and improved plasticity (A(5)).

The strength of Al-Mg-Si-Mn casting alloy strongly depends on Mg content in solid solution and precipitation of strengthening phases. Alloys with the nominal composition AlMg5Si2Mn with addition of Li and Ti+Zr were studied by means of differential scanning calorimetry (DSC), transmission electron microscopy (TEM) and energy dispersive X-Ray analysis (EDX). DSC measurements show that the eutectic melting temperature was about 595°C and it is higher than that of commercial A356 casting alloy. The macro- and microhardness tests show that in as-cast state hardness were higher than for A356 and continuously growth during artificial aging. TEM investigations reveal that during artificial aging three different precipitation types are forms in the alloy matrix. Two of them belong to the different structures of Mg2Si precipitates. Appearance of the third one identified as d’-Al3Li phase represent that Al-Mg-Si system can be successfully used for designing of Li-containing casting alloy which is not developed yet.

This article presents research the results of the mechanical properties at the ambient temperatureof hypoeutectic cast silumin EN AC-AlSi7Mg0.3 (according to EN 1706:2011; analogic to alloyA356 according to AA – the Aluminum Association). As related to the commonly known and usedprocess of immersion during quenching, the research also used a micro-jet system of cooling.After quenching, the experimental samples were also submitted to artificial aging in three differentvariations. The achieved results were compared with the mechanical properties of the alloyin the as-cast state.Samples from the experimental alloy were subjected to micro-jet cooling during quenching;in principle, they had a similar level of properties as related to the samples that were cooled byimmersion; only in some cases did the micro-jet cooling give better results. Further works in the field should be aimed at constructing machines for micro-jet cooling with water pressure levelssignificantly higher than the typical pressure of community waterworks.

The structure of permanent mold and high pressure die castings of the AlMg5Si2Mn alloy after alloying with Li and Sc has been investigated by scanning and transmission electron microscopy, hardness and microhardness measurements, energy dispersive X-ray analysis. Three conditions, as cast, solution treated and aged, were investigated. It was shown that in as-cast state, the structure of an alloy having the nominal composition AlMg5Si2Mn consists of four phases: first – the Al based solid solution, second – the (Al)+(Mg2Si) eutectic, third – the primary Mg2Si crystals and fourth – the a-Al(Mn, Fe)Si phase. Similar phases were observed in the alloys containing Sc or Li. After two days of storing in an as-cast condition, the solid solution in all tested alloys decomposesand forms zebra-crossing shaped precipitates. TEM examinations revealed that these precipitates nucleate heterogeneously on dislocations. The solution treatment at 575.0°C results in spheroidization of the Mg2Si lamellas, dissolution of the precipitates and formation of a-Al(Mn, Fe)Si dispersoids, nucleating on the surfaces of Mg2Si lamellas. In the Sc containing alloys, the formation of Al3Sc was detected after 120 min soaking. Further heating resulted in the growth of these precipitates. Aging of the Al-Mg-Si alloys leads to an increase of hardness in all studied alloys. This effect is mainly related to precipitation strengthening, via solid solution decomposition and formation of b’’-phase. In Li-alloyed specimens, plates of b Mg2Si phase were observed together with small cubic-shaped d’ Al3Li precipitates. The structure of permanent mould and high pressure die castings of the AlMg5Si2Mn alloy after alloying with Li and Sc has been investigated by scanning and transmission electron microscopy, hardness and microhardness measurements, energy dispersive X-ray analysis. Three conditions, as cast, solution treated and aged, were investigated. It was shown that in as-cast state, the structure of an alloy having the nominal composition AlMg5Si2Mn consists of four phases: first - the Al based solid solution, second - the (Al)+(Mg2Si) eutectic, third - the primary Mg2Si crystals and fourth – the phase. Similar phases were observed in the alloys containing Sc or Li. After two days of storing in an as-cast condition, the solid solution in all tested alloys decomposes and forms zebra-crossing shaped precipitates. TEM examinations revealed that these precipitates nucleate heterogeneously on dislocations. The solution treatment at 575.0°C results in spheroidization of the eutectic, dissolution of the precipitates and formation of dispersoids, nucleating on the surfaces of Mg2Si lamellas. In the Sc containing alloys, the formation of Al3Sc was detected after 120 min soaking. Further heating resulted in the growth of these precipitates. Aging of the Al-Mg-Si alloys leads to an increase of hardness in all studied alloys. This effect is mainly related to precipitation strengthening, via solid solution decomposition and formation of b²-phase. In Li-alloyed specimens, plates of b Mg2Si phase were observed together with small cubic-shaped d¢ Al3Li precipitates.

The article presents the analysis of properties of the high-strength AlZnMgCu (abbr AlZn) aluminium alloy and estimates possibilities of its application for responsible structures with reduced weight as an alternative to iron alloy castings. The aim of the conducted studies was to develop and select the best heat treatment regime for a 7xx casting alloy based on high-strength materials for plastic working from the 7xxx series. For analysis, wrought AlZnMgCu alloy (7075) was selected. Its potential of the estimated as-cast mechanical properties indicates a broad spectrum of possible applications for automotive parts and in the armaments industry. The resulting tensile and fatigue properties support the thesis adopted, while the design works further confirm these assumptions.

The studies regard analysis of variable Al and Fe additions on the chosen group of CuSn alloys. The group of tin bronzes known and applied for thousands of years has still found its application in many branches of industry, however it was observed that small amounts of aluminum and iron may affect the original properties strongly. The changes of mechanical properties and microstructure is discussed in detail. Aside of many advantageous properties of these bronzes, it is noted that the mentioned alloying additions have beneficial effect on the gas-induced shrinkage porosity. Simultaneously, the effect of the aluminum addition on the characteristic phase transformation points was determined basing on the analysis of calorimetric curves. The results are correlated with microstructure observations.

Modern development of technology features not only dynamic changes aimed at improving the performance characteristics of structural components through the optimum selection of materials, adjustments in design, or upgrade of manufacturing processes, but also the increase of the economic impact resulting from these changes. All of these processes occur under one common name of conversion and have a simple or – more often complex character (due to the vast scope of changes introduced). This article examines some basic definitions related to the concept of conversion and its association with innovative and intelligent solutions currently applied in materials engineering. Due to a variety of problems, attention was focused on the core notions related to conversion. Basing on our own experience (i.e., on the experience of the Foundry Research Institute and AGH University of Science and Technology in Krakow) and also on foreign achievements in this particular field of knowledge (mainly coming from the US), the most interesting examples of the conversion of materials and design (in the authors’ opinion) were discussed with reference to the methods of manufacture and possible interactions.

Issues connected with high quality casting alloys are important for responsible construction elements working in hard conditions. Traditionally, the quality of aluminium casting alloy refers to such microstructure properties as the presence of inclusions and intermetallic phases or porosity. At present, in most cases, Quality index refers to the level of mechanical properties – especially strength parameters, e.g.: UTS , YS, HB, E ( Young’s Modulus ), K 1c (stress intensity factor). Quality indexes are often presented as a function of density. However, generally it is known, that operating durability of construction elements depends both on the strength and plastic of the material. Therefore, for several years now, in specialist literature, the concept of quality index ( QI ) was present, combines these two important qualities of construction material. The work presents the results of QI research for casting hypoeutectic silumin type EN AC-42100 (EN AC-AlSi7Mg0.3), depending on different variants of heat treatment, including jet cooling during solution treatment.

During the research a group of copper and tin alloys was investigated. The influence of variable additions of aluminium within the range of 0.3 – 1.4 wt % was analysed on tin bronze CuSn10 with the aim of obtaining durable bronzes, from outside the normalized copper alloy groups. Melts were conducted in order to obtain alloy samples for testing the chosen properties. Metallographic and SEM-EDS tests were carried out to determine the microstructure changes caused by introducing Al addition to CuSn10 alloy. Also, chosen mechanical properties were tested for the alloys investigated. The results showed considerable changes in the microstructure as well as significant hardening of the Cu-Sn alloys as the result of aluminium addition. The thermal and dilatometric analysis confirmed the presence of phase changes, also their parameters were assessed depending on the share of aluminium addition in the CuSn10. The aluminium additive applied within the range of 0.3-1.4 wt% to CuSn10 bronze clearly impacted the microstructure and the strength properties analysed, causing the increase in strength and hardness with simultaneous insignificant decrease of elongation of the CuSn10Al alloys.

This article presents the possibility of decreasing dispersed shrinkage microporosity in castings of hypoeutectic alloying silumins, as a result of narrowing – within the standards or industrial specifications – the content of particular elements of the chemical composition: alloying additionsand/or impurities. This relatively-simple and, at the same time, inexpensive method can often lead to a quick solution of this type of defects in castings and the improvement of their tightness. In order to orientate the chemical composition towards an optimal content computer-aided statistical processing was conducted (using Statistica Ver. 9 software) with the application of figures directly related to shrinkage microporosity as well as indirectly related to the temperature rangeof crystallisation (ΔT = Tlik – Tsol). This data came from literature and MAGMASoft® software for simulations of pouring and solidification processes in castings. The achieved results were verified under industrial conditions.

The work presents the test result of the influence of cooling rate on the microstructure of AZ91 alloy, Vickers micro-hardness and Brinell hardness. Studies cooling and crystallization of AZ91 alloy was cast into the ceramic shells pre-heated to 180 ° C and then air-cooled at ambient temperature or intensively super cooled in the liquid coolant. The TDA method was applied to record and characterize the thermal effect resulting from the phase transformations occurring during the crystallization of AZ91 alloy. The kinetics and dynamics of the thermal processes of crystallization of AZ91 alloy in the ceramic shells were determined. Metallographic tests were performed with the use of an optical microscope. A comparison of these test results with the thermal effect recorded by way of the TDA method was made. Influence of cooling rate of AZ91 on HV0, 01 micro-hardness and Brinell hardness alloy was examined.