This is an open access article under the CC BY license: Al-Khwarizmi Engineering Journal Al-Khwarizmi Engineering Journal ISSN (printed): 1818 – 1171, ISSN (online): 2312 – 0789 Vol. 20, No. 4, December (2024), pp. 89-98 Enhancing the Surface Mechanical Properties of AL2618 Alloy 3O2sing a PLD Device with AIU sTurbocharger Sarah S. Faraj1, Nabil H. Hadi2* Department of Mechanical Engineering, University of Baghdad, Baghdad, Iraq 1 Departments of Aeronautical Engineering, University of Baghdad, Baghdad, Iraq 2 *Corresponding Author, s Email: Dr.Nabil.Hassan@coeng.uobaghdad.edu.iq (Received 29 April 2024; Revised 18 June 2024; Accepted 28 July 2024; Published 1 December 2024) https://doi.org/10.22153/kej.2024.07.004 Abstract Pulsed laser deposition (PLD) has become a widely used technology for fabricating multicomponent thin films. In this research, nanomaterial Alfa-Al2O3 with a particle size of 30 ± 5 nm was deposited on the surface of AL-2618 alloy turbine blades. The microstructure, phase composition and the effects of a coating made from Alfa-Al2O3 nanomaterial were studied. PLD was employed to improve the mechanical performance of the aluminium alloy (AL-2618) used in turbocharger blades, primarily to reduce corrosion and erosion. To ensure high hardness and extended fatigue life, a 10 μm layer of aluminium dioxide was deposited on the surface of the aluminium alloy using PLD. The mechanical properties of the blade improved, as shown by hardness tests conducted on the samples. An energy-dispersive X-ray spectroscopy test was conducted before and after deposition. After depositing a nanolayer of Al2O3, the mechanical properties were enhanced. The hardness of the samples increased from 685 HLD to 781 HLD, and corrosion and erosion were reduced. The atomic percentage of oxygen deposited on the blade surface ranged from 0.6% to 0.8%, and the surface roughness (x) decreased from 49.5 µm to 22.8 µm because of the nanolayer applied via PLD. Keywords: Turbocharger Blade; Surface Improvement; Nanomaterial (Alfa- Al2O3), Corrosion; Erosion; PLD 1. Introduction Since the early 20th century, precipitates have been used to reinforce various alloys. In recent decades, extensive research has focused on alloys with nanostructured (NS) or ultrafine-grain (UFG) structures, both of which share the challenge of poor ductility [1]. The precipitation behaviour in NS or UFG alloys differs from that in their conventional coarse-grained counterparts. However, adding precipitates has been proven to be a viable technique for resolving the strength–ductility tradeoff. A review of precipitation’s scientific discovery in the last 20 years in NS or UFG alloys is presented in this article. The study covered the growth and formation mechanism of precipitates, their interactions with dislocations, grain boundaries or solid solutes and the resulting mechanical behaviour [1]. Pulsed laser deposition (PLD) is the most common physical method for thin films, obtaining a coating with qualitative specifications and inappropriate vacuum media. When an electrical discharge occurs between two electrodes under relatively low pressure, a beam with high-energy ions is generated to extract atoms from the surfaces of the targets when they collide [2]. The growing need for robust, lightweight materials has led to the development of numerous families of age-hardenable aluminium alloys. Precise control over the formation of alloy microstructures during solidification and subsequent thermomechanical processing is essential for producing high-quality, reliable cast and wrought products. The development of an equiaxed, fine-grained structure in castings has long mailto:Dr.Nabil.Hassan@coeng.uobaghdad.edu.iq https://doi.org/10.22153/kej.2024.07.004 https://doi.org/10.22153/kej.2024.07.004 Sarah S. Faraj1 Al-Khwarizmi Engineering Journal, Vol. 20, No.4, P.P. 89- 98 (2024) 90 been known to improve mechanical properties, reduce hot tearing and boost feeding to eliminate shrinkage porosity, resulting in a more uniform, finer distribution of second phases [3]. A thin film is a layer deposited onto a substrate with the objective of improving the physical properties of the surface for specific applications. Multiple layers, such as double, triple or quadruple, can be deposited simultaneously in a single layer [4]. Several methods are used to create thin films, one of which is plasma deposition, performed at low temperatures. Operating at low temperatures activates chemical reactions. Aluminium and its alloys are critical in various industries due to their excellent physical properties, high strength-to- weight ratio, strong corrosion resistance, ease of processing and forming, non-toxicity and recyclability [5, 6]. The Al-Cu-Mg-Fe-Ni forging alloy, known as aluminium alloy 2618, was developed for use in aerospace engine components and automotive applications. Its excellent high- temperature strength, reaching up to 238 °C, is achieve a combination of precipitation and dispersion hardening [7-11]. Corrosion is a modern dilemma, as the damage it causes to tools and equipment leads to substantial material and financial losses. Corrosion occurs in various forms and can be categorised into two main types: wet corrosion and dry corrosion. Wet corrosion is a corrosion process in which the liquid phase plays a key role, either through direct interaction or by serving as a medium for the reaction. On the contrary, dry corrosion involves the direct interaction between gas or vapour and the corroded material, without the presence of a liquid phase. Corrosion can be defined as the chemical interaction between a material and the surrounding atmosphere in direct contact with it, whether the atmosphere is air or any other chemical environment [12-14]. This study enhances the mechanical properties of turbocharger surfaces by depositing a thin film of aluminium dioxide (Al2O3) onto samples manufactured from aluminium alloy (AL2618). The coated samples were then tested for use in the manufacturing of turbocharger blades to achieve a protective layer with high efficiency, increased hardness and enhances corrosion resistance. 1.1 Pulsed laser deposition device PLD has gained popularity in the production of multi-component thin films. High-temperature superconductors, compound semiconductors, dielectrics, ferroelectrics, gigantic magnetoresistance and electro-optic oxides, polymers and diverse heterostructure types have been extensively researched [15] by Heidelberg (1996) with a third edition scheduled for release in 2000. Large grain orientation and epitaxial films are produced by ablating the target material at pressures below 0.1 mb, either in an inert, reactive environment or in a vacuum. The primary mechanism for film formation involves the flow of atoms and ions interacting with molecules on the substrate surface. Assuming the creation of small- area films, measuring several square millimetres, PLD is a fast, simple and highly reliable process for experimentation. Thin films can be produced using a variety of materials without the need for hazardous or corrosive processes. The quick turnaround times enable the thorough examination of a wide range of chemicals and film doping variations. These factors make PLD especially appropriate for materials research and development. The target material is ablated at pressures of approximately 0:01 to produce epitaxial and large-grain-oriented films, either in inert or reactive atmospheres, or in a vacuum. In this process, small molecules and atoms/ions striking the substrate surface are the main sources of flux used to synthesise the films. The situation changes remarkably from one to several hundred mb. These circumstances encourage vapour-phase condensation and the formation of clusters and nanocrystals. These nanocrystals contain 102–106 atoms, with sizes ranging from 1–20 nm [16]. 1.2 Alfa- Al2O3 layers Alpha alumina (α-Al2O3) content determination is one of the primary applications of X-ray diffraction (XRD) analysis. However, notable variations are observed in the relative intensities of the principal XRD reflections depending on the morphological shapes of rhombohedral alumina due to the preferred orientation effect). Moreover, the X-ray diffraction power of a specimen may vary, complicating or eliminating the use of a reference material. As a result, comparing the intensities of certain reflections from a sample to those of a reference material can lead remarkable analytical errors. Using conventional XRD coupled with the Rietveld approach, the concentrations of alpha and beta alumina (β-Al2O3=Na2O•11Al2O3) were investigated in nine commercial ceramic alumina, three NIST standards and two unique grades of alumina. The morphology of the materials were also assessed using scanning electron microscopy (SEM) [17]. Sarah S. Faraj1 Al-Khwarizmi Engineering Journal, Vol. 20, No.4, P.P. 89- 98 (2024) 91 2. Experimental Work This experiment was conducted under the following conditions: pressure of 3.3 *10−2 bar, energy of 1520 MJ, frequency of 10 Hz and 500 impulses, as shown in Figure 1. After completing the deposition process, the turbine blade was examined at the Industrial Research and Development Center, where the properties of the blade were improved using the PLD device. A nanomaterial (ALfa- Al2O3) with a particle size of 30 ± 5 nm was deposited on the surface of the turbine blade (AL-2618). The device setup technical parameters are as follows: wavelengths of 532, 1064 and 1320 nm; pulse width of 10 ns; energy of 20— 2000 mj; working frequency of 1–10 Hz; spot diameter of 1–8 mm; cooling method of water cooling + air cooling; total power of 300 W. The force applied by the Al2O3 particles to slow down recrystallisation can be expressed as follows [18]: pz = 3fγ/2r. (1) The average size of the particles (Al2O3) is r = (30 ± 5) * (10−7) m, the volume fraction is f = 0.83%, and the boundary energy is γ = 53.75 J/m2. According to the computation, the force Pz exerted by the Al2O3 particles is 15.6 MPa. Recrystallisation is prevented more effectively in 2618-(Al2O3) than in AA2618 because more Al2O3 particles exist in the latter. Similarly, the grain boundary velocity in 2618-(Al2O3) is lower than in AA2618 for the same reason (pz = 22.30 MN). Fig. 1. Pulsed Laser Deposition Device 3. Results and Discussion 3.1 EDX test Energy-dispersive X-ray spectroscopy (EDX) examination is the first step in material analysis. The distinctive pattern of the absorption bands indicates an improvement in the material composition as the chemical composition of small particles changes. The results showed an increase in compressive strength, enhanced ductility and higher hardness after depositing a layer of Al2O3 on the composite material using glow discharge plasma, as shown in Figure 2. A. Before Deposition without Filter B. After Deposition without Filter C. Before Deposition with Filter D. After Deposition with Filter Sarah S. Faraj1 Al-Khwarizmi Engineering Journal, Vol. 20, No.4, P.P. 89- 98 (2024) 9 Fig. 2. (EDX) Examination for Turbocharger Blades The atomic and weight percentages of oxygen (O) increased because of the deposition, whereas those of aluminium (Al) decreased. Tables 1–2 show the atomic and weight percentages for elements O and Al before and after deposition. Table 1 (EDX) Examination for Turbocharger Blades before Deposition Table 2 (EDX) Examination for Turbocharger Blades after Deposition 3.2 Hardness test When determining a material’s hardness, the Brinell and Rockwell procedures require considerable force and create a broad surface impression. Although optical measurement is incorporated into the Vickers hardness testing method, it is unsuitable for permanently assembled components or machinery that has been installed. Leeb hardness testing instruments use indirect and rebound techniques to quantify hardness. However, notable differences are found when converting Leeb hardness values to Brinell, Rockwell and Vickers hardness scales. Ultrasonic hardness testers, on the contrary, leave a small imprint on the surface of the material and quantify hardness using the high- accuracy ultrasonic contact impedance (UCI) method. Nonetheless, an ultrasonic hardness tester tends to be more expensive due to its high level of precision and nearly nondestructive nature of the assessment it provides [19]. The technical details are as follows: measurement range of 170–960 HLD; measurement direction of 0°–360°; hardness scale of HL, HB, HRB, HRC, HRA, HV and HS. Figure 3 shows that the maximum load values are 500 N, 50 kg, 110 Lb and 1800 Oz; the load division values are 0.1 N, 0.01 kg, 0.01 Lb and 1O z; the accuracy is ±1％. The results of the hardness test for turbocharger blades before and after deposition are displayed in Table 3 and Figure 4. Fig. 3. Hardness Tester Element Atomic % Atomic % Error Weight % Weight % Error O 3.6 0.6 2.2 0.3 Al 96.4 0.3 97.8 0.3 Element Atomic % Atomic % Error Weight % Weight % Error O 13.8 0.8 8.7 0.5 Al 86.2 0.3 91.3 0.3 Sarah S. Faraj1 Al-Khwarizmi Engineering Journal, Vol. 20, No.4, P.P. 89- 98 (2024) 93 Table 3, Hardness Test for Turbocharger Blades. Sample number. Before deposition (HLD) After deposition (HLD) 1 685 781 (a) Before deposition (HLD) (b) After deposition (HLD) Fig. 4. Hardness Tester for Turbocharger Blades 3.3 Surface topography using AFM test Atomic force microscopy (AFM), also known as scanning probe microscopy, provides near-atomic resolution images for measurement. AFM can measure surface roughness down to the angstrom scale. In addition to surface images, AFM analysis can offer quantitative estimates of feature sizes, such as step heights and other dimensions. The distinctive pattern of absorption bands indicates an improvement. Figures 5–8 illustrate the decline in the value of x from 49.5 µm to 22.8 µm. Moreover, qualitative mapping of additional physical characteristics, such as adhesion, modulus, dopant distribution, conductivity, surface potential, electric field and magnetic domains, may be achieved using sophisticated AFM measurement modes. Sarah S. Faraj1 Al-Khwarizmi Engineering Journal, Vol. 20, No.4, P.P. 89- 98 (2024) 94 A- 2D B- 3D Fig. 5. AFM Tester for Turbocharger Blades before Deposition. Fig. 6. AFM Tester Parameters for Turbocharger Blades before Deposition. Sarah S. Faraj1 Al-Khwarizmi Engineering Journal, Vol. 20, No.4, P.P. 89- 98 (2024) 95 A- 2D B-3D Fig. 7. AFM Tester for Turbocharger Blades after Deposition. Fig. 8. AFM Tester Parameters for Turbocharger Blades before Deposition Sarah S. Faraj1 Al-Khwarizmi Engineering Journal, Vol. 20, No.4, P.P. 89- 98 (2024) 96 4. Conclusions 1. The mechanical properties of a turbocharger blade made of aluminium alloy (AL-2618) and coated with Al2O3 are explored in this work. 2. A nanolayer of Al2O3 was deposited using a PLD device, and the samples were examined after deposition using an EDX device, hardness tester and AFM. 3. The atomic percentage of oxygen deposited on the surface of the turbocharger blade ranges from 0.6% to 0.8%. 4. 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(2024) 89-89، صفحة 4، العدد20مجلة الخوارزمي الهندسية المجلد سارة سعد فرج 98 AL2618 تحسين الخواص الميكانيكية لسطح الشاحن التوربيني المصنع من سبيكة AI2O3مع PLD باستخدام جهاز *2هاديحسن نبيل ،1فرج سعدسارة بغداد، بغداد، العراققسم الهندسة الميكانيكية، جامعة 1 أقسام هندسة الطيران، جامعة بغداد، بغداد، العراق2 Dr.Nabil.Hassan@coeng.uobaghdad.edu.iq: البريد االلكتروني* المستخلص في هذا البحث دراسة مرحلة البنية المجهرية تم .المعادن باألغشية الرقيقة لطالء سطحتقنية واسعة االنتشار (PLD) ترسيب الليزر النبضي ، وانجز الترسيب بجهاز الليزر النبضي لتحسين األداء الميكانيكي لشفرات الشاحن (Alfa- Al2O3) وتركيب وتأثير الطالء المصنع من مادة نانوية شفرات الشاحن تقليل التآكل بالكالل والتآكل الكيمياوي ل، من مميزات استخدام التقنية (AL-2618) التوربيني المصنعه من سبائك األلومنيوم من ثاني أكسيد 10μm) طبقة بسمك) يتم ترسيبالليزر النبضي بواسطه جهاز الترسيبطويل األمد، ال عمرالتوربيني ، ولضمان الصالبة العالية وال سطح الخواص الميكانيكية ل نالحظ تحسن،بعد اجراء الفحصوصات المختبريه .الشاحن التوربينيشفرات على سطح ( Al2O3األلومنيوم النانوي ) قد وجد أنه بعد ترسيب طبقة النانويةو .قبل وبعد عملية الترسيب (EDX) ( وAFM) اختباروصالبة ال اجراء اختبارحيث تم احن التوربيني.شال .زادت الصالبة وقل التآكل، (Al2O3) من ثاني أكسيد األلومنيوم mailto:Dr.Nabil.Hassan@coeng.uobaghdad.edu.iq