Cast Microstructure Research Articles

Study of Ultimate Tensile Strength and Wear Rate of Squeeze Cast Al-Si-Cu Alloy with DOM and TOPSIS Approaches

Aluminium alloys are widely used to produce aerospace and agricultural sector components. Squeeze casting (SQC) is a liquid forging process to enrich the mechanical characteristics of light metal alloy castings. Al-Si-Cu castings were fabricated through SQC process adopting Response Surface Methodology (RSM) following Box-Behnken experimental design. Fifteen castings were fabricated by varying input factors such as squeeze pressure, pouring temperature and dwell time. Optimal process parameter settings were predicted for the responses Ultimate Tensile Strength (UTS) and Wear rate by Desirability Optimization Methodology (DOM) and Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS). The details of experiments and analysis are presented. The examination of microstructure and worn-out surface of squeeze castings indicated that the refi ned grain structure due to squeeze pressure application improved UTS and Wear resistance. Confi rmatory tests were conducted for settings suggested by DOM and TOPSIS. The setting suggested by DOM resulted in greater improvement. The value of UTS and wear rate predicted with DOM were verifi ed through confi rmatory tests and the measured values are in agreement with predicted values. An optimal improvement of 99.3% and 53.75% were achieved on ultimate tensile strength and wear resistance respectively in comparison with gravity die-cast components.

Effect of the Type of Inorganic Binder on the Microstructure and Properties of AlSi7Mg Alloy Castings Made by Ablation Casting Technology.

The results of studies on the effect that the type of binder and casting technology exert on the microstructure and properties of AlSi7Mg alloy castings are discussed in this paper. Comparative tests were carried out on three casting manufacturing technologies, i.e., conventional sand mould casting and cooling process, metal mould (die) casting, and sand mould casting with ablation breakdown of mould and cooling of castings. Moulds were made from four different sand mixtures with inorganic binders hardened by various technologies. The microstructure of test castings was examined at three different levels, i.e., in the upper part, central part, and lower part of each casting. The tensile test at room temperature was carried out in accordance with standards. The experimental results showed differences in the microstructure of castings. The differences resulted from changes in the crystallisation path due to the use of three different casting technologies, ensuring different rates of heat dissipation from castings; they were also due to the shape of castings. It has been shown that castings made by ablation technology are characterised by a high degree of the microstructure refinement (SDAS reduced by 18–30%), which gives higher strength properties than the properties of castings made in conventional sand moulds. Samples taken from castings made by the ablation technology in moulds with phosphate binder and microwave-hardened geopolymer binder were characterised by the mechanical properties comparable to gravity die castings.

ОСОБЕННОСТИ СТРУКТУРЫ ТОНКИХ ОБРАЗЦОВ ИЗ СТАЛИ 20ГЛ, ПОЛУЧЕННЫХ ЛИТЬЕМ ПО ГАЗИФИЦИРУЕМЫМ МОДЕЛЯМ

The work is devoted to the study of carbon liquation in cast steel samples with a thickness of 8 mm obtained by a special method of casting according to gasified models (LGM). In the course of the work, steel castings with a thickness of 8 mm were obtained. The microstructure of castings was studied both before heat treatment and after TO (annealing). Studies have shown that in the process of pouring metal during the destruction of expanded polystyrene, intensive carburization of steel occurs not only in the surface area, but also throughout the cross-section of the samples. Traditional heat treatment of steel castings (annealing) does not have a significant effect on the redistribution of carbon in the volume of the casting, that is, it does not reduce the carbon liquation along the sample cross-section.

Assessment of mechanical properties of LM13 aluminum alloy hybrid metal matrix composites

Aluminium LM13 alloy based hybrid particulate composites have been processed by adding boron carbide (B4C) and titanium diboride (TiB2) particles. The wt% of titanium diboride (TiB2) is varied as 0, 3, 6, 9, 12, 15 and a constant 3 wt% of boron carbide is used to prepare the composites. Stir cast route is used to fabricate the composites. The microstructures of castings are examined using computer aided image analyzer. Vicker hardness, yield strength, ultimate tensile strength and energy absorbed by the composites are examined and reported. The results show that uniform dispersion of TiB2 and B4C reinforcement phases in Al LM13 alloy. Micro hardness of composites enhanced upto 36.6% when compared to Al alloy reinforced with 3 wt% of B4C particles. Ultimate tensile strength of Al alloy is improved from 151 MPa to 192 MPa by reinforcing 15 wt% of titanium diboride particles. LM13 aluminium alloy hybrid particulate composites offers superior vicker hardness, yield strength, utlimate tensile strength and impact strength over LM13 aluminium alloy based single particle reinforced composites.

Analysis of microstructure and fatigue of cast versus selective laser-melted dental Co-Cr alloy

Statement of problemThe forces exerted on teeth and prostheses during mastication are repeated and dynamic, resulting in fatigue damage to dental prostheses. Most fractures of dental restorations are fatigue failure. The 4-point bend fatigue behavior of Co-Cr-Mo-W alloys manufactured by investment casting (CAST) and selective laser melting (SLM) has received little attention. PurposeThe purpose of this in vitro study was to evaluate the 4-point bend fatigue property of dental Co-Cr alloys and determine the relationship between microstructure and the 4-point bend fatigue property of Co-Cr alloys created by traditional casting and SLM. These can guide the use of Co-Cr alloy in dentistry. Material and methodsCo-Cr-Mo-W alloys were fabricated with a dimension of 45×2×2 mm by investment casting and SLM. The 3-point bend test measured the ultimate bend strength with 3 specimens in each group. The 4-point bend fatigue test evaluated the fatigue life under various stresses, with 6 specimens in each group. The specimens were mechanically ground, polished, and electrochemically etched. Scanning electron microscopy was used to identify the microstructures of both etched specimens and fracture surfaces. X-ray diffraction investigations were used to determine the phases. Significant differences in the bend strength were analyzed by using the independent samples t test (α=.05), and the fatigue test was analyzed with ANCOVA (α=.05). ResultsThe mean ±standard deviation bend strength of SLM specimens was 1837 ±3 MPa, higher than the 1200 ±6 MPa for CAST specimens (P<.05). The maximum bend stress of the SLM specimens without fatigue failure was 735 MPa, which was statistically higher than the 394 MPa for CAST specimens (P<.05). The microstructure characteristics of the SLM alloy contributed to its excellent fatigue performance. In SLM alloy, the γ phase constituted the majority with some ε and Laves phases, while the cast alloy possessed higher ε and Laves phases. The grains of SLM alloy were equiaxed and fine, and the second phases were fine and dispersive. In contrast, the cast alloy possessed clear dendrites, and the second phases were sizable. ConclusionsThe SLM dental Co-Cr-Mo-W alloy had statistically better 4-point bend fatigue properties than cast alloy, which was associated with an improved microstructure.

Microstructure and mechanical properties of electron beam welded TiZrNbTa refractory high entropy alloy

It is stringent to develop welding techniques for refractory high entropy alloys (RHEAs) to fabricate large-sized components, since it is difficult to fabricate large-sized RHEA castings because of their poor fluidity and severe element segregation. Here, we first time utilize electron beam welding (EBW) to join TiZrNbTa RHEA, and a defect-free joint is successfully achieved. After EBW, a coarse casting microstructure is largely refined with the reduction of casting porosities. The average hardness in the entire joint is almost uniform, which is the comprehensive effect between the weakening of solution strengthening and the grain refinement strengthening. The tensile strength of the joint achieves 940 MPa, with a high strength efficiency of 90%. This study provides a way to fabricate large-sized RHEA components.

Improving the technology of late inoculation in the production of thin-walled castings from ductile iron

The article presents the results of evaluating the impact of late inoculation on formation the microstructure of thin-wall castings from ductile iron. Existing hypotheses about the mechanism of formation and growth of graphite inclusions in the iron are analyzed. The analysis of the existing theories makes it possible to predict the high efficiency of inoculation treatment as close as possible to melt crystallization. It is noted that idea of late treatment is in introducing of inoculants into the iron melt in the pre-crystallization period, what make it is possible to provide high inoculation impact on the molten metal by creating additional crystallizing nuclei of graphite. Presented type of inoculation treatment makes it possible to obtain the required shape and diameter of nodular graphite, its uniform distribution, increase the area of graphite inclusions, reduce risk of shrinkage defects, and prevent the formation of cementite. In the presented research work the late inoculation was carried out by integrating of solid inserts of the INOCSIL&reg; series produced by NPP Technology Company in the gating feeding system of the mould on the existing foundry factory. It is given the results of metallographical tests of samples from the castings obtained both by the current inoculation treatment of iron and by late inoculation treatment technology. The analysis of results of metallographical research showed the high efficiency of late inoculation compare with the existing technology of ladle treatment on the foundry. The use of late inoculation treatment technology made it possible to improve the microstructure of metal and increase the elongation by more than two times.

Influence of Al/Ti Ratio and Ta Concentration on the As-Cast Microstructure, Phase Composition, and Phase Transformation Temperatures of Lost-Wax Ni-Based Superalloy Castings.

The as-cast microstructure, alloying element segregation, solidification behavior, and thermal stability of model superalloys based on Inconel 740 with various Al/Ti ratios (0.7, 1.5, 3.4) and Ta (2.0, 3.0, 4.0 wt%) concentrations were investigated via ThermoCalc simulations, scanning and transmission electron microscopy, energy-dispersive X-ray spectroscopy, dilatometry, and differential scanning calorimetry. The solidification of the superalloys began with the formation of primary γ dendrites, followed by MC carbides. The type of subsequently formed phases depended on the superalloys’ initial Al/Ti ratio and Ta concentration. The results obtained from solidification simulations were compared to the obtained microstructures. For all castings, the dendritic regions consisted of fine γ′ precipitates, with their size mainly depending on the initial Al/Ti ratio, whereas in the interdendritic spaces, (Nb, Ta, Ti)C carbides and Nb-rich Laves phase precipitates were present. In high Al/Ti ratio superalloys, β-NiAl precipitates, strengthened by η and α-Cr phases, were observed. Based on dilatometric results, the dissolution of γ′ precipitates was accompanied by a substantial increase in the coefficient of thermal expansion. The end of the dilatation effect took place around the γ′ solvus temperature, as determined via calorimetry. Moreover, the bulk solidus temperature was preceded by the dissolution of the Laves phase, which may be accompanied by local melting.

Microstructural Design of the Cast Iron via Laser Hardening with Defocused Beam of the Continuous Wave CO2 Laser

The cast iron is widely used in mechanical parts due to its good properties, as damping, good fluidity, resistance to deformation, excellent machinability and low cost. However, the number of its applications are reduced because its low corrosion, wear and friction resistance. The microstructure of the metallic materials has high influence on these properties. Laser hardening can improve these properties via designing of the microstructure. The evaluation of the laser parameter influence on the microstructural features is vital for a correct design of the microstructure and therefore, good improvement of the metallic material properties. Although the various laser parameter influence has been analysed on sundry papers, the influence of the distance from focal point and scan speed in the laser hardening microstructures has been rarely evaluated in the literature. Thus, the influence of this parameter on the microstructures generated through laser hardening is the subject matter of this work. The experiments were carried out with continuous wave carbon dioxide laser on samples of ground cast iron. The atmosphere was air flow at 0.7MPa, the laser operated at 100W and the scan rates were 1mm/s and 5mm/s. The distances to focal point of the laser beams ranged from 0.0mm to 5.6mm. The microstructures of the samples were revealed via nital and evaluated with optical microscopy. This work shown that the microstructure of gray iron cast can be designed by mean of laser hardening. In addition, laser hardened zones had various microstructures (e.g. austenitic, martensitic, pearlite and dendritic). The type of the microstructures in laser treated zones was determined by distance from focal point and scan speed. Moreover, the width and the depth of the laser hardened zones were generally enlarged with the increasing of the distance from focal point. Furthermore, the laser irradiation at slow rates, i.e. 1mm/s, produced laser hardened zones larger than laser scan at 5mm/s. In future works, the hardness, wear and friction resistance of the laser hardened samples will be evaluated because the literature review indicates that austenitic and martensitic microstructures show high values of these properties.

Microstructure, Phase Formation and Heat-Treating of Novel Cast Al-Mg-Zn-Cu-Si Lightweight Complex Concentrated Aluminum Based Alloy

In the current work, a novel complex concentrated aluminum alloy is designed and studied. In order to investigate the unknown region of the multicomponent phase diagrams, thermo-physical parameters and the CALPHAD method were used to understand the phase formation of the Al58Mg18Zn12Cu5Si7 at.% (Al47.4Mg13.3Zn23.8Cu9.6Si6wt.%) alloy with a low-density of 2.63 g/cm3. The CALPHAD methodology showed good agreement with both the investigated microstructure and the thermodynamic parameters. The designed alloy was manufactured using an induction furnace and pour mold casting process. This study avoids the use of expensive, dangerous or scarce alloying elements and focuses instead on the utilization of widely available relatively cheaper elements. The microstructural evolution as a function of the heat-treatment was studied by means of different microstructural characterization techniques. The hardness, compressive strength and electrical conductivity of the as-cast and heat-treated alloy at room temperature were studied and correlated with the previously characterized microstructure. The alloy is characterized by a multiphase microstructure with major α-Al matrix reinforced with various secondary phases. In terms of mechanical properties, the developed alloy exhibited a high hardness value of 249 Vickers and compressive strength of 588 MPa. The present work provides a valuable insight for researchers, who aim to design and produce industry-like Aluminum based complex concentrated alloys (CCAs).

Mechanisms and kinetics of (de-)protection of soil organic carbon in earthworm casts in a tropical environment

Earthworms have potential to stabilize soil organic carbon (SOC), but the biophysical controls on SOC dynamics in earthworm casts and the SOC residence time in casts is poorly known. To this end, we aimed to investigate (1) the kinetics of SOC (de-) protection in earthworm casts deposited in a tropical environment and (2) changes in the spatial relationships between fresh particulate organic matter (POM) and pore architecture within casts. Our experimental approach was to espose casts produced by the anecic earthworm Amynthas adexilis to tropical temperature and rainfall by placing them in a woodland in northern Vietnam. For 400 d, we monitored the dynamics of cast microstructures using X-ray micro-computed tomography and compared them to those of the surrounding soil aggregates (control). We also measured potential CO2 emissions of the same samples in a laboratory incubation. As expected, recently egested casts had higher SOC (1.9-fold) and POM volumes (7-fold) than aggregates, whereas their total imaged porosity was 4 times less. The SOC of casts was more labile than SOC of aggregates, as casts had 3 times more potentially mineralizable SOC. By 72 d of exposure to field conditions, the casts and aggregates had similar potential SOC mineralization, indicating that they had developed a similar level of SOC protection. Temporal changes in SOC mineralization rates were related to variations in POM volume, particularly those connected to the outside of the cast. After 400 d of exposure, casts had still greater POM volumes (2.5-fold) and higher SOC contents (1.6-fold) but similar total imaged porosity and SOC stability as aggregates. In conclusion, these results clearly indicated the direct involvement of earthworms in SOC stabilization through their impact on POM and pore spatial arrangements, which may have led to prolonged SOC sequestration for > 400 d.

Assessment of the Quality and Mechanical Parameters of Castings Using Machine Learning Methods.

The aim of the work is to investigate the effectiveness of selected classification algorithms and their extensions in assessing microstructure of castings. Experiments were carried out in which the prepared algorithms and machine learning methods were tested in various conditions and configurations, as well as for various input data, which are photos of castings (photos of the microstructure) or information about the material (e.g., type, composition). As shown by the literature review, there are few scientific papers on this subject (i.e., in the use of machine learning to assess the quality of the microstructure and the obtained strength properties of cast iron). The effectiveness of machine learning algorithms in assessing the quality of castings will be tested using the most universal methods. Results obtained by classic machine learning methods and by neural networks will be compared with each other, taking into account aspects such as interpretability of results, ease of model implementation, algorithm simplicity, and learning time.

Impact of thermal exposure on the microstructure and mechanical properties of a twin-roll cast Al-Mn-Fe-Si strip

Al-Mn-Fe-Si strips were fabricated via both the twin-roll casting (TRC) and the more conventional route, direct-chill casting (DC). The two types of strips prepared were subjected to thermal exposure at a series of temperatures. Uniaxial tensile tests after the thermal exposure showed that while the DC strip presented a ∼74% decrease in the yield strength and ∼35% decrease in the ultimate tensile strength (UTS) after being exposed to 350 °C for 12 h, the TRC strip, in contrast, maintained its strength at temperatures up to ∼460 °C for the same duration. Systematic microstructure characterization revealed that the different thermal stability in the strength of the two types of strips arised from their distinct evolution in grain morphology and second phase particles during the thermal exposure. The calculation based on Cahn-Lücke-Stüwe (CLS) model suggested that due to the highly supersaturated solute atoms, at the beginning of the thermal exposure, the TRC strip experienced a strong solute drag which reduced the grain boundary migrating velocity to a value that is orders of magnitude smaller than that in the DC strip. With the progress of the thermal exposure, the solute atoms precipitated out, forming densely distributed second phase particles. For one thing, these particles stabilized the grain structure by inducing Zener pinning pressure which could be ten times higher than that in the DC strip, depending on the temperature. For another, they acted as dislocation obstacles and compensated for the strength loss owing to decreasing solution hardening. Both effects contributed to the TRC strip's fairly stable strength regarding thermal exposure below 460 °C. The present work could guide the direct application of the TRC strips in the industry. The results should also be helpful for the development of a fundamental framework for designing advanced TRC Al strips with improved mechanical properties at elevated temperatures.

Thermodynamic and Kinetic Calculation of High Strength Aluminum-Lithium Alloy

High strength Al-Li alloy is the research focus of aluminum alloy. In the present paper, high strength Al-Li alloy 2A97 composed of Al-Li-Cu-Zn-Mg-Mn-Zr system is studied by thermodynamic and kinetic calculation. The equilibrium phase diagram and the metastable phases of 2A97 were calculated by thermodynamic method. The solidification phase diagram of 2A97 was obtained using the Scheil–Gulliver model. The continuous cooling transformation diagram and isothermal aging curves were calculated using the kinetic method. In addition, the 2A97 microstructures of cast, homogenized, hot-rolled, and solid solution were observed by a scanning electron microscope. The results can be used for the process optimization and microstructure control of 2A97. In particular, the research results of this work can be used for the determination of the homogenization temperature and solid-solution temperature.

Effect of Nano-Sized TiC-TiB2 on Microstructure and Properties of Twin-Roll Cast Al-Cu-Mn-Zr Alloy

Al-5Cu-0.8Mn-0.1Zr strips produced during a twin-roll-casting process are investigated in this paper. Central segregation does occur in the alloy strip, and the segregation is a mixture of Al2Cu and Al20Cu2Mn3 eutectic phases. This mixture is difficult to be dissolved in solid solution heat treatment. In this paper, nano-sized TiC/TiB2 particles are introduced in the process of twin-roll-casting. It was found that after adding 0.3% nano-sized TiC-TiB2 particles, the composition distribution becomes more uniform, and the central segregation is eliminated, compared to the strip without nanoparticles. The tensile strength of T6-treated alloy increases from 350 MPa to 390 MPa when nanoparticles are added, and the goal of increasing the properties of twin-roll-cast Al-Cu-Mn-Zr alloy has been achieved.

Metallurgical and corrosion characterization of warring states period bronzes excavated from Pujiang, Chengdu, China

Located in Pujiang, Chengdu, China, more than four hundred artifacts were unearthed during the excavation of the Warring States (the Warring States period lasts from 475 to 221 BC) ship-shaped graves in 2016. The compositional and metallurgical feature of the unearthed vessels are still unclear. Archaeologists and conservators are puzzled by such problems that need to be answered by systematic scientific studies. Fifty one samples, either from the matrix (26 samples), or from the corrosion part (25 samples) of 25 unearthed bronze vessels, were carefully collected from the fallen part of the bronze vessels for analysis. Technical methods, such as OM, SEM-EDS, XRD and Raman Spectroscopy were adopted for compositional and metallurgical characterization of the bronzes, as well as identification of the corrosion products. The bronzes are Cu–Sn–Pb trinary alloys with typical casting microstructure. The proportion of Sn are in accordance with excavated bronze vessels in surrounding areas. Recycling isn’t involved with the production of such vessels. Layered structure of the corrosion products was observed. Different corrosion products were identified as Cu2CO3(OH)2, Cu2O, CuSO4·5H2O SnO2, PbSO4 and PbCO3. The findings help us gain insights into the bronze manufacturing in Bashu district, as well as the corrosion behavior in certain condition.

Microstructural and Tribological Evaluation of Brake Disc Refurbishing Using Fe-Based Coating via Directed Energy Deposition

In this paper, the refurbishing of worn-out brake discs by coating with powder via direct energy deposition (DED) is evaluated. A medium carbon steel powder was used to coat cast-iron discs. Deposition of this steel was carried out directly on the disc surface or, alternatively, after a previous deposition of a buffer layer made of stainless steel. It was seen that the use of a buffer layer ensured a good coating adhesion, despite the formation of cast microstructures at the interfaces between the disc and the two different coatings (buffer and outer layer). Coated discs were tested against two different Cu-free commercial friction materials to evaluate their tribological properties. Very similar friction coefficients, specific wear rates, and total emissions were measured for both friction materials sliding against the coated disc. These tribological data are slightly higher with respect to those obtained in the case of an uncoated disc, suggesting that improvement of the top coating composition and surface finishing is necessary in order to achieve better performances.

A review on friction stir processing over other surface modification processing techniques of magnesium alloys

An enormous amount of research has been conducted on aluminium alloys in friction stir processing (FSP), despite magnesium alloys reporting severe weight reduction when compared to aluminium alloys; a very slight amount of research has testified for FSP of magnesium alloys. Magnesium is highly reactive and susceptible to corrosion in the presence of an aggressive environment. This highly corrosive nature of magnesium limits its applications. Surface properties like crystal structure, composition, and microstructure influence the corrosion and wear properties of the material. Coating techniques and alloying techniques like laser surface modifications are performed to passivate the magnesium surface from corrosion. Coating techniques, however, have been found to be insufficient in corrosion protection due to coating defects like pores, cracks, etc, adhesion problems due to poor surface preparation of the substrate, and impurities present in the coating which provide microgalvanic cells for corrosion. The current study gives a detailed overview of different types of surface modification methods, such as physical vapour deposition, chemical vapour deposition, chemical conversion coating, and ion implantation coating techniques, and also focuses on a few alloying or surface processing methods, such as laser surface modification – namely laser surface melting, laser surface cladding, laser shot peening, laser surface alloying and FSP. FSP is a novel surface modification method derived from friction stir welding, which modifies the microstructure and composition of surface layer without changing the bulk properties to enhance corrosion resistance. FSP enhances and homogenizes the microstructure but also eliminates the breakup of the brittle-network phases and cast microstructure imperfections. Indeed, FSP can produce particle and fibre-reinforced magnesium-based surface composites. FSP empowers the manufacturing of magnesium by adding additives. The different methods of coating and surface modification are compared with FSP.

An overview of the effect of stirrer design on the mechanical properties of Aluminium Alloy Matrix Composites fabricated by stir casting

An overview of the effect of stirrer design on the mechanical properties of Aluminium Alloy Matrix Composites fabricated by stir casting

Effect of the Biodegradable Component Addition to the Molding Sand on the Microstructure and Properties of Ductile Iron Castings.

In this work, the results of the examinations of the effect of the mold material and mold technology on the microstructure and properties of the casts parts of ductile cast iron have been presented. Four different self-hardening molding sands based on fresh silica sand from Grudzen Las, with organic binders (no-bake process), were used to prepare molds for tested castings. A novelty is the use of molding sand with a two-component binder: furfuryl resin-polycaprolactone PCL biomaterial. The molds were poured with ductile iron according to standard PN-EN 1563:2018-10. The microstructure of the experimental castings was examined on metallographic cross-sections with PN-EN ISO 945-1:2019-09 standard. Observations were made in the area at the casting/mold boundary and in a zone approximately 10 mm from the surface of the casting with a light microscope. The tensile test at room temperature was conducted according to standard PN-EN ISO 6892-1:2016-09. Circular cross-section test pieces, machined from samples taken from castings, were used. In the present experiment, it was stated that interactions between the mold material of different compositions and liquid cast iron at the stage of casting solidification led to some evolution of casting’s microstructure in the superficial layer, such as a pearlite rim observed for acidic mold sand, a ferritic rim for alkaline sand, and graphite spheroids degeneration, especially spectacular for the acidic mold with polycaprolactone (PCL) addition. These microstructural effects may point to the interference of the direct chemical interactions between liquid alloy and the components released from the mold sand, such as sulfur and oxygen. Particularly noteworthy is the observation that the use of molding sand with furfuryl resin with the addition of biodegradable PCL material does not lead to an unfavorable modification of the mechanical properties in the casting. The samples taken from Casting No. 2, made on the acidic molding sand with the participation of biodegradable material, had an average strength of 672 MPa, the highest average strength UTS-among all tested molding sands. However, the elongation after fracture was 48% lower compared to the reference samples from Casting No. 1 from the sand without the addition of PCL.