<4D6963726F736F667420576F7264202D20CDD3EDE420C7E1DAE1DFC7E6ED20E6C7D3EDE120E6DAC8C7D339312D203938> Al-Khwarizmi Engineering Journal Al-Khwarizmi Engineering Journal,Vol. 13, No. 3, P.P. 91- 98 (2017) Influence of Nanoreinforced Particles (Al2O3) on Fatigue Life and Strength of Aluminium Based Metal Matrix Composite Alalkawi Hussain J. M.* Aseel A. Hamdany** Abbas Ahmed Alasadi*** *,**Department of Electromechanical Engineering/ University of Technology ** Department of Mechanical Engineering/ University of Al-Mustansiriyah *Email: alalkawi2012@yahoo.com **Email: aseelbaky@yahoo.com ***Email: dr.abbas_alasadi@yahoo.com (Received 5 December 2016; accepted 28 March 2017) https://doi.org/10.22153/kej.2017.03.005 Abstract In this investigation, Al2O3 nano material of 50nm particles size were added to the 6061 Al aluminium alloy by using the stir casting technique to fabricate the nanocomposite of 10wt% Al2O3. The experimental results observed that the addition of 10wt% Al2O3 improved the fatigue life and strength of constant and cumulative fatigue. Comparison between the S-N curves behaviour of metal matrix (AA6061) and the nanocomposite 10wt% Al2O3 has been made. The comparison revealed that 12.8% enhancement in fatigue strength at 107cycles due to 10wt% nano reinforcement. Also cumulative fatigue life of 10wt% nanocomposite was found to be increased by 33.37% and 39.58% for low-high and high-low loading sequences, respectively, compared to the metal-matrix cumulative life. Keywords: Al2O3 nanoparticles, AA6061/10wt%, constant and cumulative fatigue, MMCs. 1. Introduction Fatigue life and strength are the most important parameters in which the stress failure occurs less than the allowable stresses because of combined loading; prediction of its value can avoid catastrophic in machines at the service [1]. Metal matrix composites have been studied and are widely used in an industry for several applications in aerospace, automotive and others [2-5]. Estimating fatigue life is an important parameter to design equipment with safety. A full fatigue fracture behaviour have been studied for Al-SiC nano-metal composite MMCs with 50 nm particles size, different vol.% up to 6 nanocomposites have been fabricated to find optimum fatigue behaviour, it was examined the internal fracture surface of the same nano-metal composite, a ductile-brittle fracture with an increase in the ductile fracture at higher nano- particles within higher fractions [2]. The fatigue behaviour of aluminium (AA2014) alloy reinforced with micro and nano-sized alumina particles Al2O3 have studied for their structural applications. Microscope examinations by high resolution (TEM) images were used to evaluate the fatigue behaviour of the composite samples. It was found improving in the mechanical and fatigue properties by the nano- alumina reinforced Al-composites. Compared to the micron sized alumina reinforced composites. The failure cycle was observed to be higher for the nano alumina reinforced composites in comparison with micron sized alumina composites due to a lower order of induced plastic strain [3]. Fatigue parameters have studied on Al reinforced with (SiC) particulates. Comparison have mode based on the matrix aluminium alloy Alalkawi Hussain J. M. Al-Khwarizmi Engineering Journal, Vol. 13, No. 3, P.P. 91- 98(2017) 92 containing Si. The different weight percentages of SiC particulates in the size range of some different µm were used. Fatigue tests indicated that the nanocomposite fatigue resistance increased with increasing content of SiC particulates. SiC particulates improved fatigue resistance which acting as barriers to cracks deflecting the growth plane of cracks resulting in decreased crack propagation rates [4]. Experimental work carried out to find the fatigue properties of Al-matrix nanocomposites using friction stir processing technique (FSP). Aluminium alloy (AA5052) with different amounts of nanoparticles up to 6 stages were fabricated to get homogenous dispersion of nano- particles inclusions. Microstructural studies of high resolution techniques showed that nano- metric Al3Ti with different nano-particles in size were scattered throughout a fine-grained Al matrix (<2 µm) an improvement in the tensile strength and hardness was attained. Uniaxial stress-controlled tension– tension fatigue testing (R = 0.1) were applied to estimate the fatigue characterization of the nanocomposites alloy. The results were compared with the un-processed (annealed) and FSPed alloy without pre-placing TiO2 particles. It was found that FSP of the aluminum alloy increased the fatigue strength (at 10 7 cycles) for about 28% and 32% compared with the annealed specimen when the concentration of the reinforcing particles was 2 and 3.5 vol. %, respectively [5]. The aim of the present work is to investigate the fatigue properties (life and strength) under interaction of nanomaterial as reinforcement with the AA 6061 Al alloy as metal-matrix. 10wt% Al2O3 nanoparticles were added to Al 6061 metal- matrix for manufactured the nanocomposite and tested under fatigue condition to determine the life and strength of nanocomposite. 2. Experimental Work This section focuses on the materials used and its chemical composition, mechanical properties in addition of nanocomposite manufacturing and the tensile testing. 2.1. Selection of Materials The matrix metal used for the present work is 6061 Al alloy. It is widely used the alloy easy to manufacture, preparation and available. Table (1) gives the chemical composition in wt% of the matrix used. Table 1, Chemical analysis of 6061 Al. alloy examined at state company for inspection and engineering (SIER) wt. % in comparison with Ref [6]. Elements wt.% Cr Zn Co Si Ti Mn Mg Fe others Al Standard [6] 0.04- 0.35 Max 0.25 0.15- 0.4 0.4-0.8 Max0.1 5 0.8-1.2 Max 0.15 Max 0.7 0.05 Balance Experimental according to SIER 0.18 0.13 0.28 0.61 0.08 0.96 0.11 0.54 - Balance The mechanical properties of 6061 Al. alloy compared with Ref [6] are summarized in Table (2). Table 2, Mechanical properties of 6061 Al. alloy tested at SIER compared with the findings of Ref [6]. 6061 Al properties Hardness HB Strength σσσσu (MPa) Yield stress σσσσy (MPa) Modules of elasticity (GPa) Ref.[6] 30 149.76 138.06 70-80 Experimental SIER 32 154 140 74 2.2. The Reinforced Material Hard particles like Al2O3 are usually used as reinforced material in the (MMCs) metal-matrix composites (MMCs).The above particle is commonly used with aluminium as reinforcement and the application of the Al2O3/Al composites in the aircraft industries, automotive where the tribological characterization is very important [7]. Alalkawi Hussain J. M. Al-Khwarizmi Engineering Journal, Vol. 13, No. 3, P.P. 91- 98(2017) 93 For present work the adopted reinforced material used in manufacturing the nanocomposite is Al2O3 with the particle size of 50nm. The chemical analysis of the reinforced material can be shown in table (3). Table 3, Chemical analysis of Al2O3 wt%.[8]. Element Cao TiO2 Fe2O3 others Alumina Wt.% 1.1 1.8 0.8 0.02 97 2.3. Composites Preparation The stir casting method used for preparation the 6061Al/Al2O3 composites. The reinforced particles were preheated to 200°C before putting into the melt. The stirrer speed of 450 rpm and the casting temperature was 850°C. More details of the test rig which used to prepare the nanocomposite can be seen elsewhere [9]. Thus, the nanocomposite of 10%Al2O3 was obtained in the form of rod of diameter 12 mm and length of about 100mm. The reason of selection 10wt% Al2O3 based on the findings of Ref [10] who found that the maximum improvement in mechanical properties was occurred at 10wt% Al2O3 reinforcement. 2.4. Fatigue Specimen Geometry The material was received from the casting moulds as 12 mm in diameter and 100mm length. 12 specimens with nano and 12 specimens as received were manufactured using programmable CNC lathing machine by writing a suitable programme. Then all specimens were machined. Careful attention was done to produce good surface finish and to reduce the tensile residual stresses. The surface of all specimens were polished using 260, 300, 400, 600, 800, and 1000 silicon carbide papers and after that three different diamond laps, course 3/2 micron, fine 1 micron and finally extra-fine 1/4 micron. The last stage was cleaning by distilled water then washing the specimens for polishing with alcohol. The specimens were numbered and tested for measuring the roughness of selected specimens. Table 4, Selective surface roughness results of 8 specimens. Specimens No 1 3 5 7 9 11 13 15 Ra µm 0.4 0.28 0.5 0.44 0.6 0.66 0.36 0.49 Rt µm 1.2 0.9 1.32 1.07 1.4 1.44 0.96 1.02 The fatigue test specimen can be illustrated in Fig. (1). Fig. 1. The specimen dimensions in mm according to (DIN 50113) standard values. 2.5. Fatigue Test Machine A rotating bending machine fatigue–testing Schenck product type was used to implement all fatigue tests, with constant and variable amplitude. The fatigue specimen which is shown in Fig. (1) Has a round cross section and is subjected to an applied load form the right side of the perpendicular to the axis of specimen, developing a bending moment. Therefore the surface of the specimen is under tension and compression stress when it rotates. The value of the load (P) is measured by Newton (N), applied to the specimen for a known value of stress (σ) measured by (N/mm 2 ) and used from applying the relation below: ������ = 32 × 125.7 × ���� � × �� Where d (mm) is the minimum diameter of the specimen, and force arm is equal to 125.7mm, and [11]. The fatigue test rig is shown in Fig (2). Alalkawi Hussain J. M. Al-Khwarizmi Engineering Journal, Vol. 13, No. 3, P.P. 91- 98(2017) 94 Fig. 2. Fatigue bending machine test. 3. Results and Discussions 3.1. Constant Fatigue Results The specimens were tested under constant amplitude fatigue, stress at room temperature (RT), to estimate the S-N curves .The results of this series are illustrated in Table (5) and Figure (3). Table 5, S-N curve results of Al6061 and Al6061/10 wt. % nanocomposite. Al6061 metal-matrix Al6061-10 wt% nanocomposite Specimen No. Applied stress(MPa) Nf cycles Specimen No. Applied stress(MPa) Nf cycles 1 2 3 140 6500 12000 8000 16 17 18 140 8800 11000 12500 4 5 6 120 18600 22600 25000 19 20 21 120 24600 30000 26000 7 8 9 100 43200 48000 40000 22 23 24 100 72000 66000 74200 10 11 12 80 118000 135000 127000 25 26 27 80 205000 217600 225000 13 14 15 60 380000 405600 422000 28 29 30 60 510000 525000 49800 Fig. 3. S-N curves for both 6061 Al and 10wt% nanocomposite. From table (5), the best fit equation which accurately describe the behaviour of the metal and the nanocomposite is the Basquin formula which can be written in the form. �� = ��� � …(1) Where a, b are material constants. These constants can be obtained by the equations � = � ∑ ��� ����� !��"∑ �� ��� ∑ �� !�� # �$ # �$% # �$% � ∑ &�� !��' ( ")∑ �� !�� # �$% * (# �$% ...(2) And +,-� = ∑ �� ���"� ∑ �� !�� # �$% # �$% � …(3) Where h is the number of test specimens Applying the above equations to the experimental data in table (5), the Basquin equations with their correlation coefficient (R 2 ) can be seen in table (6). Table 6, Basquin equations with correlation factor for metal and composite. 6061 Al alloy 6061 Al /10wt% nanocomposite Improvement factor (IF) for fatigue endurance limit �� = 1099�� "0.112 R2=0.9962 �� = 1055�� "0.132 R2 =0.983 12.28% IF is calculated from the equation, 45 = �6.7�898:� "�6 .7�;<=9>� �6.7�898:� ∗ 100 Where �@.A is endurance limit stress (MPa). The �@.A was calculated from the Basquin equation at 10 7 cycles. The results revealed that �@.A�CDEF�� = 87.3 MPa and �@ .A�HFH�� = 99.53 MPa. IF (improvement factor was found to be 12.28% due to nanomaterial addition. Many workers focused on the fatigue properties such as Akio et.al. [12] and Mussert et.al.[13]. They Alalkawi Hussain J. M. Al-Khwarizmi Engineering Journal, Vol. 13, No. 3, P.P. 91- 98(2017) 95 tested nanocomposite under fatigue cycling and they concluded that the nano reinforced work to strengthen the metal matrix and to enhance the fatigue strength of nanocomposites. Hafeez and Senthil [14] found that the ceramic particles strengthen the metal-matrix composite fatigue properties (fatigue strength), maintaining good ductility at high temperature creep resistance. 3.2. Cumulative Fatigue Results Cumulative fatigue tests were carried out at the same conditions for S-N curve i-e room temperature (RT) and stress ratio (R=-1). Table (7) gives the experimental results obtained for materials, metal-matrix and nanocomposite (MMCs). Table 7, Cumulative fatigue results for metal-matrix and nanocomposite (MMCs). Specim en No Loading sequences (MPa) Metal- matrix 6061 Al Nanocomposite 6061 Al/10wt% Al2O3 Loading programme 31 32 33 80-120 34600 38000 44000 51000 60000 64000 34 35 35 120-80 30000 31000 26000 42000 48000 54000 The improvement in cumulative fatigue lives due to 10wt% nanomaterial Al2O3 can be illustrated in table (8). Table 8, Shows the improvement factor in cumulative fatigue live due to 10wt% Al2O3. Loading sequences (MPa) Nf average metal-matrix Nf average nanocomposite IF 80-120 38867 58333 33.37% 120-80 29000 48000 39.58% The results of table (8) are plotted in Fig. (4). Fig (4) shows the enhancement of cumulative fatigue lifes. Fig. 4. Improvement of cumulative fatigue life due to 10wt% Al2O3. The applications of nanocomposites based on aluminium alloy as a metal-matrix and Al2O3 nano-reinforced material are commonly used in aircraft industries, space applications and automotive where the fatigue and tribological properties are required [15]. Comparison has been made between the MMCs and metal matrix and the comparison revealed that the MMCs have better fatigue resistance [16]. It is observed from the constant and cumulative fatigue testing; tables (5), (7) that the nanocomposite of 10wt% Al2O3 achieved higher fatigue strength and life. The reasons may be the followings: 1. Uniform dispersion of Al2O3 particles in the nanocomposite [17]. 2. Less porosity and homogeneous dispersion of Al2O3 which in turn increased the mechanical Alalkawi Hussain J. M. Al-Khwarizmi Engineering Journal, Vol. 13, No. 3, P.P. 91- 98(2017) 96 and fatigue properties .Porosity should be kept to minimum level [18]. 3. Al2O3 addition increases brittleness in which the mechanical and fatigue properties increased [19]. 4. The fine size of the particles leads to improve the mechanical and fatigue properties. 5. Good thermal bounding between the 6061 Al. alloy and the reinforced material the attribute to enhance fatigue behaviour [2]. 6. The high mechanical properties of Al2O3 itself leads to enhance the fatigue strength and life [6]. 4. Conclusions A fundamental understanding of the mechanism which provides the enhancement in fatigue properties is required and the following remarks derived from this work are concluded. 1. The fatigue strength of 10wt% Al2O3 nanocomposite at 10 7 cycles was improved by 12.28% compared to as cast Al 6061 alloy. 2. The cumulative fatigue lives of the 10wt% Al2O3 nanocomposite were enhanced by 33.37% for low-high loading and 39.58% for high-low loading 3. The above improvements of the nanocomposite may be due to uniform distribution, less porosity , high bounding between Al2O3 and 6061 Al. alloy, high dislocation density, high mechanical properties of Al2O3 itself. Acknowledgments The authors are grateful to the University of Technology/Department of Electromechanical engineering for the provision of laboratory facilities. 5. References [1] H. K. D. H. Bhadeshia, "Steels for Bearings", Progress in Materials Science, 57: 268-435, 2012. [2] H. G. Yazdabadi, A. Ekrami, H.S. Kim, and A. Simchi," An Investigation on the Fatigue Fracture of P/M Al-SiC Nanocomposites Meatallurgical" Materials Transactios A, Vol. 44A, 2013. [3] R. Senthilkumar, N. Arunkumar, M. M. Hussian,"A comparative study on low cycle fatigue behaviour of nano and micro Al2O3 reinforced AA2014 particulate hybrid composites", Results in Physics, Vol. 5, 273– 280, 2015. [4] C. Kaynak, S. Boylu,"Effect of SiC particulates on the fatigue behaviour of an Ai- alloymatrix composite", Materials and Design, Vol.27, 2006. [5] P. S. Zangabad, F. Khodabakhshi, A. Simchi , A.H. Kokabi,"Fatigue fracture of friction-stir processed Al–Al3Ti–MgO hybrid nanocomposites", International Journal of Fatigue, Vol.87 ,266–278, 2016. [6] V. Bharath, N Mahadev., V. Auradi, "Preparation characterization and mechanical properties of Al2O3 reinforced 6061 Al particular MMCs", International Journal of Eng. Research and Technology (IJERT) vol.1 issue 6, 2012. [7] A. Mazahery, H. Abdizadeh, HR Baharandi, "Development of high-performance A356/nano- Al2O3 composites", Materi. Sci. Eng. 518, 61-64, 2009. [8] O. S.Mohsen, A. Mazhery,"Aluminium-matrix nanocomposites swarm intelligence optimization of the microstructure and mechanical properties", Materials and Technology 46, 6,613, 2012. [9] H.J.M Alalkawi., A. A. Alrasiaq, M. A. A. Al Jaafari," Performance study on mechanical properties in 7075 aluminium alloy and Al2O3 nanocomposite" Journal of Eng, and Tech., accepted for publication 2017. [10] H.J.M Alalkawi, H. A. Alsalihi,”An investigation of some mechanical properties of 6061 A alloy /10 wt% Al2O3 nanocomposite". [11] N. M Abdulmuhssan., A. H, Hamed. and H. J.,M. Al-Alkawi, "Effect of Temperature on Fatigue Transition life and Strength of Aluminium alloy", Engineering and Technology Journal, VoL.30, N0.6, 2012. [12] K. Akio, O. Atsushi, K. Toshiro, T. Hiroyuki, “Fabrication process of metal produced by vortex method", J. Japan Inst. Light Met., 49, pp. 149–154, 1999. [13] K. M. Mussert , W. P. Vellinga, A. Bakker S. Van, D. Zwaag, "A nano-indentation study on the mechanical behaviour of the matrix material in an AA6061 - Al2O3 MMC",J. Mater. Sci., 37, Issue 4, pp.78-794, 2002. [14] H. Ahamed , V. S. Kumar," Role of nanosize reinforcements", J. of. Alloys and compounds, 505, pp 772-782, 2010. Alalkawi Hussain J. M. Al-Khwarizmi Engineering Journal, Vol. 13, No. 3, P.P. 91- 98(2017) 97 [15] A. Mazaherg, H. Abdizadeh ,H.R.Baharrandi, "Development of high performance A356/nano Al2O3 composites", Materials Science and Engineering, A 518, 61–64, 2009. [16] R.H. Jones, C.A. Lavender, M. T. Smith ," Yield Strength-Fracture toughness Relationships in Metal matrix composites ", Scripta Metallurgica, 21,Issu 11, 1565- 1570,1987. [17] M. Singla, D.D. Dwivedi, L. Singh, V. Chawla ,"Development of Aluminium based silicon carbide Particulate metal matrix composite", J.of Minerals and materials characterization and Engineering , vol.8, No.6, pp 455-467, 2009. [18] R. K. Bhushan, S. Kumar, S. Das, "Fabrication and characterization of 7075 Al. alloy reinforced with SiCparticulaters", Intern. J. of advanced manufacturing Technology 65, 611-624, 2013. [19] A. Singh, L. kumar, M. Chaudhary, O. Narayan, P. Sharma, P.Singh, B C.Kandpal, S. Ashotosh,"Manufacturing of AMMCs Using Stir Casting Process and Testing its Mechanical Properties ", Int. J. Adv. Eng. Tech 26-29, 20 )2017( 91-98، صفحة 3د، العد13دجلة الخوارزمي الهندسية المجلم حسين جاسم العلكاوي 98 االساس ي) على عمر ومقاومة الكالل لمركب ذ3O2Alتاتير حبيبات المادة النانوية المقواة ( المعدني **الباقي الحمداني اسيل عبد العلكاوي* حسين جاسم محمد ***عباس احمد االسدي الجامعة التكنولوجية *،**قسم هندسة الكهروميكانيك/ قسم الهندسة الميكانيكية/ الجامعة المستنصرية * alalkawi2012@yahoo.com*البريد االلكتروني: aseelbaky@yahoo.com**البريد االلكتروني: dr.abbas_alasadi@yahoo.com***البريد االلكتروني: الخالصة باستخدام تقنية السباكة بالتحريك لتصنيع AA6061 نانوميتر الى سبيكة االلمنيوم 50ذات حجم حبيبات 3O2Alفي هذا البحث تم اضافة المادة النانوية وزنية حسنت من عمر بوصفه نسبة %3O2Al 10wt.النتائج المستخرجة عمليا اوضحت ان اضافة 3O2Alمن المادة النانوية %10wtالمركب النانوي ذو .واوضحت المقارنة %3O2Al 10wtوالمركب النانوي AA6061للمعدن االساس N-Sمقاومة الكالل الثابت والمتراكم .تمت مقارنة بين سلوك منحنيات و% %33.37اكمي ازداد نسبة للمادة المقواة. كذلك وجد ايضا ان عمر الكالل التر %10wدورة نتيجة 710في مقاومة الكالل عند %12.8تحسن بمقدار .واطئ على التوالي مقارنة مع العمر التراكمي للمعدن االساس-ومن عالٍ عالٍ -للتحميل المتتابع من واطئ 39.58