The Effect of Rapid Deformation Process to Improve Creep and Tensile Resistance of AZ91 Magnesium Alloy Plates

Document Type : Original Article


1 Mechanical Engineering, Shahid Rajaee Teacher Training University, Tehran, Iran

2 Materials Engineering, Shahid Rajaee Teacher Training University, Tehran, Iran


Demand for increasing strength to weight ratio, elimination of electromagnetic waves, and vibration damping has led to the wide application of magnesium-base alloys such as AZ91 in various industries like aerospace, military, vehicle, and shipbuilding. However, because of the unstable secondary particles and casting defects located on the rough grain boundaries and in the dendritic regions, due to sliding of the grain boundary, the creep resistance and tensile strength of Mg alloys at high temperatures reduce. To improve the high-temperature properties, rapid deformation processes such as friction stir processing can be employed. In this study, the influence of multi-pass friction stir processing on microhardness, tensile, and creep behavior of AZ91 at several temperatures from 25 to 210 °C has been studied. Optical microscopy and scanning electron micrograph were used to study the microstructure of the cast and processed samples and Clemex commercial software was used for grain size measurement. The experimental results indicated that at room temperature, the microhardness, tensile, and creep strength of the processed samples as compared to the unprocessed ones increased by 23, 29 and 38%, respectively. In addition, after multi-pass friction stir processing, the tensile and creep strength of the samples at 210 °C  increased by 31 and 47%, respectively. Also, the average grain size of the multi-passed friction stir processed AZ91 alloy decreased by 88%. The maximum ultimate tensile strength of 276 MPa was obtained at the tool rotational speed of 1200 r/min, the traverse speed of 60 mm/min, and the tool tilt angle of 3°. The empirical results indicated that this rapid deformation process can be useful in enhancing the mechanical properties of AZ91 alloy at high temperatures.


1.     Mordike, B. and Ebert, T., "Magnesium: Properties—applications—potential", Materials Science and Engineering: A,  Vol. 302, No. 1, (2001), 37-45. DOI: 10.1016/S0921-5093(00)01351-4
2.     Wang, Y., Huang, Y., Meng, X., Wan, L. and Feng, J., "Microstructural evolution and mechanical properties of mgznyzr alloy during friction stir processing", Journal of Alloys and Compounds,  Vol. 696, No., (2017), 875-883. DOI: 10.1016/j.jallcom.2016.12.068
3.     Mansoor, B. and Ghosh, A., "Microstructure and tensile behavior of a friction stir processed magnesium alloy", Acta materialia,  Vol. 60, No. 13-14, (2012), 5079-5088. DOI: 10.1016/j.actamat.2012.06.029
4.     Sato, Y., Park, S., Matsunaga, A., Honda, A. and Kokawa, H., "Novel production for highly formable mg alloy plate", Journal of Materials Science,  Vol. 40, No. 3, (2005), 637-642. DOI: 10.1007/s10853-005-6301-1
5.     Luo, X., Cao, G., Zhang, W., Qiu, C. and Zhang, D., "Ductility improvement of an az61 magnesium alloy through two-pass submerged friction stir processing", Materials,  Vol. 10, No. 3, (2017), 253. DOI: 10.3390/ma10030253
6.     Gangil, N., Maheshwari, S. and Siddiquee, A.N., "Influence of tool pin and shoulder geometries on microstructure of friction stir processed aa6063/sic composites", Mechanics & Industry,  Vol. 19, No. 2, (2018), 211. DOI: 10.1051/meca/2018010
7.     Kordestani, F., Ghasemi, F.A. and Arab, N.M., "An investigation of fsw process parameters effects on mechanical properties of pp composites", Mechanics & Industry,  Vol. 17, No. 6, (2016), 611. DOI: 10.1051/meca/2016012
8.     Buffa, G., Hua, J., Shivpuri, R. and Fratini, L., "A continuum based fem model for friction stir welding—model development", Materials Science and Engineering: A,  Vol. 419, No. 1-2, (2006), 389-396. DOI: 10.1016/j.msea.2005.09.040
9.     Cavaliere, P. and De Marco, P., "Fatigue behaviour of friction stir processed az91 magnesium alloy produced by high pressure die casting", Materials Characterization,  Vol. 58, No. 3, (2007), 226-232. DOI: 10.1016/j.matchar.2006.04.025
10.   Feng, A. and Ma, Z., "Enhanced mechanical properties of mg–al–zn cast alloy via friction stir processing", Scripta materialia,  Vol. 56, No. 5, (2007), 397-400. DOI:  10.1016/j.scriptamat.2006.10.035.
11.   Sun, N. and Apelian, D., "Friction stir processing of aluminum cast alloys for high performance applications", Jom,  Vol. 63, No. 11, (2011), 44-50. DOI: 10.1007/s11837-011-0190-3
12.   Raja, A. and Pancholi, V., "Effect of friction stir processing on tensile and fracture behaviour of az91 alloy", Journal of Materials Processing Technology,  Vol. 248, No., (2017), 8-17. DOI: 10.1016/j.jmatprotec.2017.05.001
13.   Lu, Z.L. and Zhang, D.T., "Microstructure and mechanical properties of a fine-grained az91 magnesium alloy prepared by multi-pass friction stir processing", in Materials Science Forum, Trans Tech Publ. Vol. 850, 778-783. DOI: 10.4028/
14.   Heidarpour, A., Ahmadifard, S. and Rohania, N., "Fsp pass number and cooling effects on the microstructure and properties of az31", Journal of Advanced Materials and Processing,  Vol. 6, No. 2, (2018), 47-58. DOI:
15.   Shamsudeen, S. and Dhas, J.E.R., "Optimization of multiple performance characteristics of friction stir welded joint with grey relational analysis", Materials Research,  Vol. 21, No. 6, (2018). DOI: 10.1590/1980-5373-mr-2017-1050
16.   Govindaraju, M., Vignesh, R.V. and Padmanaban, R., "Effect of heat treatment on the microstructure and mechanical properties of the friction stir processed az91d magnesium alloy", Metal Science and Heat Treatment,  Vol. 61, No. 5-6, (2019), 311-317. DOI: 10.1007/s11041-019-00422-1
17.   Wang, Q., Xiao, L., Liu, W., Zhang, H., Cui, W., Li, Z. and Wu, G., "Effect of heat treatment on tensile properties, impact toughness and plane-strain fracture toughness of sand-cast mg-6gd-3y-0.5 zr magnesium alloy", Materials Science and Engineering: A,  Vol. 705, (2017), 402-410. DOI: 10.1016/j.msea.2017.08.100
18.   Mamaghani Shishavan, S., Azdast, T., Mohammadi Aghdam, K., Hasanzadeh, R., Moradian, M. and Daryadel, M., "Effect of different nanoparticles and friction stir process parameters on surface hardness and morphology of acrylonitrile butadiene styrene", International Journal of Engineering, Transactions A: Basics,  Vol. 31, No. 7, (2018), 1117-1122. DOI: 10.5829/ije.2018.31.07a.16
19.   Asadi, P., Mahdavinejad, R. and Tutunchilar, S., "Simulation and experimental investigation of fsp of az91 magnesium alloy", Materials Science and Engineering: A,  Vol. 528, No. 21, (2011), 6469-6477. DOI: 10.1016/j.msea.2011.05.035
20.   Swaminathan, S., Oh-Ishi, K., Zhilyaev, A.P., Fuller, C.B., London, B., Mahoney, M.W. and McNelley, T.R., "Peak stir zone temperatures during friction stir processing", Metallurgical and Materials Transactions A,  Vol. 41, No. 3, (2010), 631-640. Doi: 10.1007/s11661-009-0140-7
21.   Yu, Z., Zhang, W., Choo, H. and Feng, Z., "Transient heat and material flow modeling of friction stir processing of magnesium alloy using threaded tool", Metallurgical and Materials Transactions A,  Vol. 43, No. 2, (2012), 724-737. DOI: 10.1007/s11661-011-0862-1
22.   Shercliff, H.R., Russell, M.J., Taylor, A. and Dickerson, T.L., "Microstructural modelling in friction stir welding of 2000 series aluminium alloys", Mechanics & Industry,  Vol. 6, No. 1, (2005), 25-35. DOI: 10.1051/meca:2005004
23.   Tutunchilar, S., Haghpanahi, M., Givi, M.B., Asadi, P. and Bahemmat, P., "Simulation of material flow in friction stir processing of a cast al–si alloy", Materials & Design,  Vol. 40, (2012), 415-426. DOI: 10.1016/j.matdes.2012.04.001
24.   Jain, R., Pal, S.K. and Singh, S.B., "Finite element simulation of pin shape influence on material flow, forces in friction stir welding", The International Journal of Advanced Manufacturing Technology,  Vol. 94, No. 5-8, (2018), 1781-1797. DOI: 10.1007/s00170-017-0215-3
25.   Nie, L., Wu, Y. and Gong, H., "Prediction of temperature and residual stress distributions in friction stir welding of aluminum alloy", The International Journal of Advanced Manufacturing Technology,  Vol. 106, No. 7-8, (2020), 3301-3310. DOI: 10.1007/s00170-019-04826-4
26.   De Dear, R.J. and Brager, G.S., "Thermal comfort in naturally ventilated buildings: Revisions to ashrae standard 55", Energy and Buildings,  Vol. 34, No. 6, (2002), 549-561. DOI: 10.1016/S0378-7788(02)00005-1
27.   Assidi, M., Fourment, L., Guerdoux, S. and Nelson, T., "Friction model for friction stir welding process simulation: Calibrations from welding experiments", International Journal of Machine Tools and Manufacture,  Vol. 50, No. 2, (2010), 143-155. DOI: 10.1016/j.ijmachtools.2009.11.008
28.   Mostafapour, A., Moradi, M., Kamali, H. and Saleh Meiabadi, M., "Multi-response optimization of the mechanical and metallurgical properties of al7075-t6 deposition process on al2024-t351 by friction surfacing using rsm and the desirability approach", Iranian Journal of Materials Forming,  Vol. 7, No. 1, (2020), 100-115. DOI: 10.22099/IJMF.2020.35736.114
29.   Vahdati, M. and Moradi, M., "Statistical analysis and optimization of the yield strength and hardness of surface composite al7075/Al2O3 produced by fsp via rsm and desirability approach", Iranian Journal of Materials Forming,  Vol. 7, No. 1, (2020), 32-45. DOI: 10.22099/IJMF.2020.35554.1143
30.   Chai, F., Yan, F., Lu, Q. and Fang, X., "Microstructures and mechanical properties of az91 alloys prepared by multi-pass friction stir processing", Journal of Materials Research,  Vol. 33, No. 12, (2018), 1789-1796. DOI: 10.1557/jmr.2018.98
31.   Lu, Z., Zhang, D., Zhang, W. and Qiu, C., "Microstructure and properties of az91 magnesium alloy prepared by multi-pass friction stir processing under different cooling conditions", Journal of Aeronautical Materials,  Vol. 36, (2016), 33-38. DOI: 10.11868/j.issn.1005-5053.2016.1.006
32.   Allavikutty, R., Pancholi, V. and Mishra, B.K., Layered microstructure generated by multipass friction stir processing in az91 alloy and its effect on fatigue characteristics, in Proceedings of fatigue, durability and fracture mechanics. 2018, Springer.213-222. DOI: 10.1007/978-981-10-6002-1_17
33.   Nia, A.A., Omidvar, H. and Nourbakhsh, S., "Effects of an overlapping multi-pass friction stir process and rapid cooling on the mechanical properties and microstructure of az31 magnesium alloy", Materials & Design,  Vol. 58, (2014), 298-304. DOI:
34.   Nakata, K., Kim, Y., Fujii, H., Tsumura, T. and Komazaki, T., "Improvement of mechanical properties of aluminum die casting alloy by multi-pass friction stir processing", Materials Science and Engineering: A,  Vol. 437, No. 2, (2006), 274-280. DOI: 10.1016/j.msea.2006.07.150
35.   Venkateswarlu, G., Devaraju, D., Davidson, M., Kotiveerachari, B. and Tagore, G., "Effect of overlapping ratio on mechanical properties and formability of friction stir processed mg az31b alloy", Materials & Design,  Vol. 45, (2013), 480-486. DOI: 10.1016/j.matdes.2012.08.031
36.   Hasan, M. and Begum, L., "Semi-continuous casting of magnesium alloy az91 using a filtered melt delivery system", Journal of Magnesium and Alloys,  Vol. 3, No. 4, (2015), 283-301.DOI: 10.1016/j.jma.2015.11.005
37.   Yuan, Y., Guo, Q., Sun, J., Liu, H., Xu, Q., Wu, Y., Song, D., Jiang, J. and Ma, A., "High mechanical properties of az91 mg alloy processed by equal channel angular pressing and rolling", Metals,  Vol. 9, No. 4, (2019), 386. DOI: 10.3390/met9040386
38.   Standard, A., "E8/e8m-13a.(2013).“Standard test methods for tension testing of metallic materials.”", ASTM International,  Vol. 1, No. 1-27.
39.   Mahmudi, R., Geranmayeh, A. and Rezaee-Bazzaz, A., "Impression creep behavior of lead-free sn–5sb solder alloy", Materials Science and Engineering: A,  Vol. 448, No. 1-2, (2007), 287-293. DOI: 10.1016/j.msea.2006.10.092
40.   Miranda, R.M., Gandra, J.P., Vilaca, P., Quintino, L. and Santos, T.G., "Surface modification by solid state processing, Woodhead Publishing,  (2013). ISBN: 9780857094698
41.   El-Danaf, E.A., El-Rayes, M.M. and Soliman, M.S., "Friction stir processing: An effective technique to refine grain structure and enhance ductility", Materials & Design,  Vol. 31, No. 3, (2010), 1231-1236. DOI: 10.1016/j.matdes.2009.09.025
42.   Nascimento, F., Santos, T., Vilaça, P., Miranda, R. and Quintino, L., "Microstructural modification and ductility enhancement of surfaces modified by fsp in aluminium alloys", Materials Science and Engineering: A,  Vol. 506, No. 1-2, (2009), 16-22.DOI: 10.1016/j.msea.2009.01.008
43.   Cipoletti, D.E., Bower, A.F. and Krajewski, P.E., "Anisotropy in plastic deformation of extruded magnesium alloy sheet during tensile straining at high temperature", Integrating Materials and Manufacturing Innovation,  Vol. 2, No. 1, (2013), 81-100. DOI: 10.1186/2193-9772-2-4