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Abstract

The paper presents the research results of the influence of the precipitation hardening on hardness and microstructure of selected Al-Si and Al-Cu alloys obtained as 30 mm ingots in a horizontal continuous casting process. The ingots were heat treated in process of precipitation hardening i.e. supersaturation with subsequent accelerated or natural ageing. Moreover in the range of the study it has been carried out investigations of chemical constitution, microscopic metallographic with use of scanning electron microscope with EDS analysis system, and hardness measurements using the Brinell method. On basis of obtained results it has been concluded that the chemical constitution of the investigated alloys enables to classify them into Al alloys for the plastic deformation as EN AW-AlSi2Mn (alternatively cast alloy EN AC-AlSi2MgTi) and as EN AW-AlCu4MgSi (alternatively cast alloy EN AC-AlCu4MgTi) grades. Moreover in result of applied precipitation hardening has resulted in the precipitation from a supersaturated solid solution of dispersive particles of secondary phases rich in alloying element i.e. Si and Cu respectively. In consequence it has been obtained increase in hardness in case of AlSi2Mn alloy by approximately 30% and in case of AlCu4MgSi alloy by approximately 20% in comparison to the as-cast state of continuous ingots.
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Authors and Affiliations

T. Wróbel
P.M. Nuckowski
P. Jurczyk
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Abstract

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.
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Authors and Affiliations

J. Augustyn-Pieniążek
S. Rzadkosz
H. Adrian
M. Choroszyński
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Abstract

The study presents methods to be used for improving the performance parameters of car engine pistons made of EN AC-AlSi12CuNiMg alloy according to the PN-EN 1706: 2011. Pistons of slow sucking and turbocharged engines were researched. A solution heat and ageing treatments were applied according to four variants. Temperatures of the solution heat treatment were: 550 ±5°C; 510°C ±5°C; and alternate: 276 ±5°C/510 ±5°C. The solution time ranged from 6 min to 4 h. Temperatures of the ageing heat treatment were 20°C and 250°C, while the ageing time ranged from 1,5 to 3h. Natural ageing was performed in 5 days. Measurements of hardness HRB and the piston diameters were performed. An improvement in the performance parameters of combustion engines was observed. Three solution heat treatment and ageing variants, allowed to obtain the pistons with hardness equal/higher than pistons of the turbocharged engines. The test results confirmed the possibility of providing a piston with properties exceeding the high load parameters specified by the manufacturer. Further studies will make it possible to improve the effects of the proposed solutions.
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Bibliography

[1] Stone, R. (2012). Introduction to Internal Combustion Engines. Fourth Edition, SAE and Macmillan.
[2] Heywood, J.B. (2018). Internal Combustion Engines Fundamentals, Second Edition, McGraw-Hill Education.
[3] Kirkpatrick, A.T. (2020). Internal Combustion Engines: Applied Thermosciences. Fourth Edition, John Wiley & Sons.
[4] Bosch, R. (2018). Automotive Handbook. 10th Edition: Robert Bosch GmbH
[5] Siemińska-Jankowska, B. & Pietrowski, S. (2003). The effects of temperature on strength of the new piston aluminum materials. Journal of KONES Internal Combustion Engines. 10(1-2), 237-250.
[6] Wajand, A., Wajand, J. (2005). Reciprocating internal combustion engines. Wydawnictwa Naukowo Techniczne PWN. (in Polish).
[7] Manasijevic, S., Pavlovic-Acimovic, Z., Raic, K., Radisa, R. & Kvrgi´c, V. (2013). Optimisation of cast pistons made of Al–Si piston alloy. International Journal of Cast Metals Research. 26(5), 255-261.
[8] Javidani, M. & Larouche, D. (2014). Application of cast Al–Si alloys in internal combustion engine components. International Materials Reviews. 59(3), 132-158.
[9] Pietrowski, S. (2001) Silumins. Łódź: Wydawnictwo Politechniki Łódzkiej. (in Polish).
[10] Poniewierski, Z. (1989). Crystallization, Structure and Mechanical Properties of Silumins. Warszawa: WNT. (in Polish).
[11] Kaufman, J.G., Rooy, E.L. (2004). Aluminum Alloy Castings: Properties, Processes and Applications. ASM International.
[12] Zolotorevsky, V.S., Belov, N.A., Glazoff, M.V. (2007). Casting Aluminium Alloys. Elsevier: Oxford, UK, pp. 327-376.
[13] Pezda, J. (2015). The effect of the T6 head treatment on change of mechanical properties of the AlSi12CuNiMg alloy modified with strontium. Archives of Metallurgy and Materials. 60(2), 627-632.
[14] Czekaj, E., Fajkiel, A. & Gazda, A. (2005). Short-lived ultrahigh temperature silicon spheroidization treatment of silumins. Archiwum Odlewnictwa. 5(17), 51-68. (in Polish).
[15] Dobrzański, L.A., Reimann, L. & Krawczyk, G. (2008). Influence of the ageing on mechanical properties of the aluminium alloy AlSi9Mg. Archives of Materials Science and Engineering. 31, 37-40.
[16] Pezda, J. (2010). Heat treatment of EN AC-AlSi13Cu2Fe silumin and its effect on change of hardness of the alloy. Archives of Foundry Engineering. 10(1), 131-134.
[17] Pezda, J. (2014). Effect of a selected heat treatment parameters on technological quality of a silumin-cast machinery components; Bielsko-Biała: ATH Scientific Publishing House: Bielsko-Biała, Poland.
[18] Pezda, J. & Jarco, A. (2016). Effect of T6 heat treatment parameters on technological quality of the AlSi7Mg alloy. Archives of Foundry Engineering. 16(4), 95-100.
[19] Czekaj, E., Kwak, Z., Garbacz-Klempka, A. (2017). Comparison of impact of immersed and micro-jet cooling during quenching on microstructure and mechanical properties of hypoeutectic silumin AlSi7Mg0.3. Metallurgy and Foundry Engineering. 43(3), 153-168.
[20] Pezda, J. & Jezierski, J. (2020). Non-standard T6 heat treatment of the casting of the combustion engine cylinder head. Materials. 13(18), 4114.
[21] Jarco, A. & Pezda, J. (2021). Effect of heat treatment process and optimization of its parameters on mechanical properties and microstructure of the AlSi11(Fe) alloy. Materials (Basel) 14(9), 2391.
[22] Nikitin, K.V., Chikova, O.A., Amosov, E.A. & Nikitin, V.I. (2016). Shortening the time of heat treatment of silumins of the Al – Si – Cu system by modifying their structure. Metal Science and Heat Treatment. 58(7), 400-404.
[23] Prudnikov, A., Prudnikov, V. (2019). The mode of hardening heat treatment for deformable piston hypereutectic silumins. International Scientific Journal Materials science. Non-equilibrium phase transformations. 5(3), 74-77.
[24] Kantoríková, E., Kuriš, M. & Pastirčák, R. (2021). Heat treatment of AlSi7Mg0.3 Aluminium alloys with increased zirconium and titanium content. Archives of Foundry Engineering. 21(2), 89-93.
[25] Kuriš, M., Bolibruchova, D. M., Matejka M. & Kantoríková, E. (2021). Effect of the precipitation hardening on the structure of AlSi7Mg0.3Cu0.5 alloy with addition of Zr and combination of Zr and Ti. Archives of Foundry Engineering. 21(1), 95-100.
[26] Rychter, T., Teodorczyk, A. (2006). Theory of piston engines. Wydawnictwa Komunikacji i Łączności. (in Polish).

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Authors and Affiliations

M. Trepczyńska-Łent
1
ORCID: ORCID
K. Műller
2

  1. Mechanical Engineering Faculty, Bydgoszcz University of Science and Technology, Al. prof. S. Kaliskiego 7, 85-796 Bydgoszcz, Poland
  2. Bergerat Monnoyeur Sp. z o.o. – Caterpillar, Poland
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Abstract

One type of spheroidal cast iron, with additions of 0.51% Cu and 0.72% Ni, was subjected to precipitation hardening. Assuming that the

greatest increase in hardness after the shortest time of ageing is facilitated by chemical homogenisation and fragmentation of cast iron

grain matrix, precipitation hardening after pre-normalisation was executed. Hardness (HB), microhardness (HV), qualitative and

quantitative metalographic (LM, SEM) and X-ray structural (XRD) tests were performed. The acquired result of 13.2% increase in

hardness after ca. 5-hour ageing of pre-normalised cast iron confirmed the assumption.

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Authors and Affiliations

T. Szykowny
M. Trepczyńska-Łent
T. Giętka
Ł. Romanowski
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Abstract

The results of studies of W-Ni-Co-Fe experimental alloy, with chemical composition assuring a possibility of producing Ni-based supersaturated solid solution are presented. The alloy was prepared from tungsten, nickel, cobalt and iron powders which were first mixed then melted in a ceramic crucible where they slowly solidified in hydrogen atmosphere. Next specimens were cut from the casting and heated at a temperature 950o C. After solution treatment the specimens were water quenched and then aged for 20 h at a temperature 300o C. The specimens were subjected to microhardness measurements and structure investigations. The latter included both conventional metallography and SEM observations. Moreover, for some specimens X-ray diffractometry studies and TEM investigations were conducted. It was concluded that quenching lead to an increase of tungsten concentration in nickel matrix which was confirmed by Ni lattice parameter increase. Aging of supersaturated solid solution caused strengthening of the Ni-based matrix, which was proved by hardness measurements. The TEM observation did not yield explicit proofs that the precipitation process could be responsible for strengthening of the alloy.
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Authors and Affiliations

M. Kaczorowski
P. Skoczylas
A. Krzyńska
J. Kaniewski
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Abstract

17-4PH stainless steel finds application in the aerospace industry owing to its good mechanical properties and corrosion resistance. In the literature, this steel is described as good for welding, but research shows that it may be problematic due to the formation of defects. In this study, the welded joints were made by the robotic TIG welding method with various welding speeds (2 and 3 mm/s). The joints were subjected to non-destructive testing and were free from defects. The microstructure was observed by light microscopy and scanning electron microscopy. Changes in the microstructure of the heat affected zone were observed and discussed. Based on the observation of the microstructure and the change in the hardness profile, the heat affected zone was divided into 4 characteristic regions. δ-ferrite and NbC were observed in the martensite matrix. The welded joints were subjected to heat treatment consisting of solution and aging in 550°C for 4 h. The microstructure of the heat affected zone become homogenized as a result of the heat treatment. The content of stable austenite in the welded joint after the heat treatment was about 3%.
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Authors and Affiliations

A. Nalborczyk-Kazanecka
1
ORCID: ORCID
G. Mrowka-Nowotnik
1
ORCID: ORCID

  1. Rzeszow University of Technology, Faculty of Mechanical Engineering and Aeronautics, 12 Powstańców Warszawy Av., 35-959 Rzeszów, Poland
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Abstract

The aim of the study was to select the optimal content of zirconium introduced as an alloying additive to obtain the best strength properties of Al-Si alloy. A technically important disadvantage is the tendency of silumins to form a coarse-grained structure that adversely affects the mechanical properties of castings. To improve the structure, modification processes and alloying additives are used, both of which can effectively refine the structure and thus increase the mechanical properties. According to the Hall-Petch relationship, the finer is the structure, the higher are the mechanical properties of the alloy. The proposed addition of zirconium as an alloying element has a beneficial effect on the structure and properties of silumins, inhibiting the grain growth. The starting material was an aluminium-silicon casting alloy designated as EN AC-AlSi9Mg (AK9). Zirconium (Zr) was added to the alloy in an amount of 0.1%, 0.2%, 0.3%, 0.4% and 0.5% by weight. From the modified alloy, after verification of the chemical composition, samples were cast into sand moulds based on a phenolic resin.
The first step in the research was testing the casting properties of alloys with the addition of Zr (castability, density, porosity). In the next step, the effect of zirconium addition on the structure and mechanical properties of castings was determined.
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Authors and Affiliations

J. Kamińska
1
ORCID: ORCID
M. Angrecki
1
ORCID: ORCID
P. Dudek
1
ORCID: ORCID

  1. Łukasiewicz Research Network – Krakow Institute of Technology, Krakow, Poland
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Abstract

The microstructural properties and hardness of a model ternary Fe-4Cr-6Ti ferritic alloy aged at 800°C for 8, 16 and 24 h are investigated in detail. Fine Fe2Ti Laves phase particles precipitate in the α-Fe (ferrite) matrix phase after solutionizing and subsequent aging treatments. The size and amount of Fe2Ti precipitates gradually increase with increasing aging time. The magnetic measurements of the aged samples confirm the variations in the microstructural properties including the volume fraction of the constituent phases, and Ti content of the α-Fe matrix phase. The mean Vickers microhardness value also increases from 203.5 to 238.4 with increasing aging time from 8 to 24 h. In addition, the cyclic oxidation behavior of 24 h aged sample, which contains maximum amount of Fe2Ti precipitates, is also investigated in detail. X-ray diffraction analysis reveals that scale product is α-Fe2O3 (hematite). Significant scale spallation and void formation is observed on the surfaces of 24 h aged Fe-4Cr-6Ti sample oxidized at 500°C.
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Authors and Affiliations

Ahmet Demirel
1
ORCID: ORCID
Emre Can Çetin
1
ORCID: ORCID
Ali Karakuş
1
ORCID: ORCID
Mehmet Şahin Ataş
1
ORCID: ORCID
Mehmet Yildirim
1
ORCID: ORCID

  1. Konya Technical University, Faculty of Engineering and Natural Sciences, Department of Metallurgical and Materials Engineering, Konya , Turkey
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Abstract

Additive manufacturing (AM) is a modern, innovative manufacturing method that enables the production of fully dense products with high mechanical properties and complex shapes that are often impossible to obtain by traditional methods. The 17-4PH grade steel is often applied where high mechanical performance is required. 17-4PH, or AISI 630, is intended for precipitation hardening, an operation that combines solution and ageing treatments and is used to significantly change the microstructure of the steel and enhance its mechanical properties. This study investigates the effect of precipitation hardening on the properties of 17-4PH steel. To examine microstructure and morphology, metallographic tests were performed together with phase composition and chemical composition analyses. Mechanical parameters were determined via Vickers hardness testing and the Oliver-Pharr method. Samples were fabricated using direct metal laser sintering (DMLS), which is one of the powder bed fusion methods. The use of a constant solution treatment temperature of 1040_C and different ageing temperatures made it possible to evaluate the effects of ageing temperature on the mechanical properties and microstructure of 17-4PH. The presence of face-centered cubic FCC g-austenite and body-centerd cubic BCC a-martensite structures were detected. The tests revealed that – similarly to the wrought material – the highest hardness of 382_10:3 HV0:2 was obtained after ageing at 450_C. The nanoindentation test showed the same H/E ratio for the sample after fabrication and after solution treatment at 0.016769, but this value increased after ageing to 127–157.5%. The sample aged at 450_C was characterized by the highest H/E ratio of 0.026367, which indicates the highest wear resistance of this material under employed treatment conditions. In general, the sample treated at 450_C showed the best performance out of all tested samples, proving to have the smallest grain size as well as high Vickers and nanoindentation hardness. On the other hand, the use of solution treatment led to reduced hardness and improved workability of the AM material.
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Authors and Affiliations

Aleksander Świetlicki
1
Mariusz Wlaczak
1
ORCID: ORCID
Mirosław Szala
1
ORCID: ORCID
Marcin Turek
2
Dariusz Chocyk
3
ORCID: ORCID

  1. Department of Materials Engineering, Faculty of Mechanical Engineering, Lublin University of Technology, Nadbystrzycka 36, 20-618 Lublin, Poland
  2. Institute of Physics, Maria Curie-Sklodowska University in Lublin, pl. M. Curie-Sklodowskiej 1, 20-031 Lublin, Poland
  3. Department of Applied Physics, Faculty of Mechanical Engineering, Lublin University of Technology, Nadbystrzycka 36D, 20-618 Lublin, Poland
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Abstract

The article focused primarily on comparing the achieved mechanical results for AlSi7Mg0.3Cu0.5Zr and AlSi7Mg0.3Cu0.5Zr0.15Ti experimental alloys. Experimental variants with the addition of Zr ≥ 0.05 wt. % demonstrated the ability of Zr to precipitate in the form of Al3Zr or AlSiZr intermetallic phases. Zr precipitated in the form of long smooth needles with split ends. When evaluating the thermal analyses, the repeated peak was observed already with the initial addition of Zr in the range of approximately 630 °C. It was interesting to observe the increased interaction with other intermetallic phases. EDX analysis confirmed that the individual phases are based on Cu, Mg but also Fe. Similar phenomena were observed in experimental alloys with a constant addition of Zr and a gradual increase in Ti by 0.1 wt. %. A significant change occurred in the amount of precipitated Zr phases. A more significant increase in mechanical properties after heat treatment of AlSi7Mg0.3Cu0.5Zr experimental alloys was observed mainly above the Zr content ≥ 0.15 wt. % Zr. The improvement of yield and tensile strength over the AlSi7Mg0.3Cu0.5 reference alloy after heat treatment was minimal, not exceeding 1 %. A more significant improvement after heat treatment occurred in modulus of elongation with an increase by 6 %, and in hardness with an increase by 7 %. The most significant drop occurred in ductility where a decrease by 31 % was observed compared to the reference alloy. AlSi7Mg0.3Cu0.5Zr0.15Ti experimental alloys, characterized by varying Ti content, achieved a more significant improvement. The improvement in tensile strength over the AlSi7Mg0.3Cu0.5 reference alloy after heat treatment was minimal, not exceeding 1 %. A more significant improvement after heat treatment occurred in modulus of elongation with an increase by 12 %, in hardness with an increase by 12 % and the most significant improvement occurred in yield strengthwith a value of 18 %. The most significant decrease also occurred in ductility where, compared to the reference alloy, the ductility drop was by up to 67 %.
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Bibliography

[1] Vončina, M., Medved, J., Kores, S., Xie, P., Cziegler, A. & Schumacher, P. (2018). Effect of molybdenum an zirconium on aluminium casting alloys. Livarski Vestnik. 68-78.
[2] Medved, J. & Kores, M.V.S. (2018). Development of innovative Al-Si-Mn-Mg alloys with hight mechanical properties. The Minerals, Metals & Materials Society. 373-380. DOI 10.1007/978-3-319-72284-9_50.
[3] Pisarek, B.P., Rapiejko, C., Szymczak, T. & Payniak, T. (2017). Effect of Alloy Additions on the Structure and Mechanical Properties of the AlSi7Mg0.3 Alloy. Archives of Foundry Engineering. 17(1),137-142. ISSN: 1897-3310.
[4] Mahmudi, R., Sepehrband, P. & Ghasemi, H.M. (2006). Improve properties of A319 aluminium casting alloy modified with Zr. Materials Letters. 2606-2610. DOI: 10.1016/j.matlet.2006.01.046
[5] Sepehrband, P., Mahmudi, R., Khomamizadeh, F. (2004). Effect of Zr addition on the aging behavior of A319 aluminium cast alloy. Scripta Materialia. 253-257. DOI: 10.1016/j.scriptamat.2004.10.025
[6] Rakhmonov, J., Timelli, G. & Bonollo, F. (2017) Characterization of the solidification path and microstructure of secondary Al-7Si-3Cu-0,3Mg alloy with Zr, V and Ni additions. Material characterization. ISSN:1044-5803.
[7] Krajewski, W., Geer, A., Buraś, J., Piwowarski, G. & Krajewski, P. (2019). New developments of hight-zinc Al-Zn-Cu-Mn cast alloys. Materialstoday Proceedings. 306-311. DOI: 10.1016/j.matpr.2018.10.410.
[8] Hermandez-Sandoval, J., Samuel, A.M. & Vatierra, F.H. (2016). Thermal analysis for detection of Zr-rich phases in Al-Si-Cu-Mg 354-type alloys. Journal of metalcasting. ISSN 1939-5981.
[9] Bolibruchova, D., Kuriš, M., Matejka, M., Major Gabryś, K., Vicen, M., (2020) Effect of Ti on selected properties of AlSi7Mg0.3Cu0.5 alloy with constant addition of Zr. Archives of Metalurgy and Materials. 66(1), 65-72. DOI: 10.24425/amm.2021.134760.

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Authors and Affiliations

M. Kuriš
1
D. Bolibruchova
1
M. Matejka
1
ORCID: ORCID
E. Kantoríková
1
ORCID: ORCID

  1. University of Zilina, Faculty of Mechanical Engineering, Department of Technological Engineering, Univerzitna 1, 010 26 Zilina, Slovak Republic

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