Experimental and Numerical Investigation on Geometric Parameters of Aluminum Patches for Repairing Cracked Parts by Diffusion Method

Document Type : Research Paper


1 Department of Mechanical Engineering, Islamic Azad University, Arak Branch, Arak, Iran

2 Department of Mechanical Engineering, Hamedan Branch, Islamic Azad University, Hamedan, Iran

3 Department of Mechanical Engineering, Faculty of Electrical, Mechanical and Computer Engineering, University of Eyvanekey, Eyvanekey, Iran



Repairing cracked aerial structures using patches is a common way to restore mechanical properties, strength and extend fatigue life. The performance of such patches can be obtained by comparing the maximum amount of force tolerated by the repaired piece with the unrepaired piece. The shape and dimensions of the patch used to repair the crack and the way the patch is bonded affect the repair quality which are of great importance. Therefore, in this paper, we investigate the factors affecting the diffusion bonding between the patch and the piece. The impact of the shape of the aluminum patch attached on a 10 mm central crack piece and perpendicular to the loading direction (mode I) is studied experimentally and numerically. The optimum conditions for the diffusion connection including the pressure, time and temperature of the connection were obtained experimentally using a composite rotatable centered design and in the connection made under these conditions, the patch shape and aspect ratio was considered as variables of design, and the results were obtained for square, rectangular, circular and elliptical patches. At the end, it was found that the best connection under the pressure conditions of 570 °C, 70 bar and 100 min was formed and the rectangular patch efficiency was greater whereas its extent is more in line with crack than the other modes. At a fixed area, the different patch geometries investigated in this study were able to influence up to 80% of the maximum force tolerated by the repaired parts. Also, there is an acceptable convergence between experimental and numerical results.


[1] Khan M.A., Kumar S., 2017, Interfacial stresses in single-side composite patch-repairs with material tailored bondline, Mechanics of Advanced Materials and Structures 25(4): 304-318.
[2] Therall E.W., 1972, Failure in Adhesively Bonded Structures, Bonded Joints and Preparatoin for Bonding, AGARD-CP-102.
[3] Baker A.A., 1984, Repair of cracked or defective metallic aircraft components with advanced fibre composites—an overview of Australian work, Composite Structures 2(2): 153-181.
[4] Ghasemi F.A., Anaraki A.P., Rouzbahani A.H., 2014, Using XFEM for investigating the crack growth of cracked aluminum plates repaired with fiber metal laminate (FML) patches, Modares Mechanical Engineering 13(14): 15-27.
[5] Ghasemi A.R., Mohammadi Fesharaki M., Mohandes M., 2017, Three-phase micromechanical analysis of residual stresses in reinforced fiber by carbon nanotubes, Journal of Composite Materials 51(12): 1783-1794.
[6] Kurgan N., 2014, Investigation of the effect of diffusion bonding parameters on microstructure and mechanical properties of 7075 aluminium alloy, The International Journal of Advanced Manufacturing Technology 71(9-12): 2115-2124.
[7] Hinotani S., Ohmori Y., 1988, The microstructure of diffusion-bonded Ti/Ni interface, Transactions of the Japan Institute of Metals 29(2): 116-124.‏
[8] Nishi H., Araki T., Eto M., 1998, Diffusion bonding of alumina dispersion-strengthened copper to 316 stainless steel with interlayer metals, Fusion Engineering and Design 39: 505-511.
[9] Yilmaz O., Aksoy M., 2002, Investigation of micro-crack occurrence conditions in diffusion bonded Cu-304 stainless steel couple, Journal of Materials Processing Technology 121(1): 136-142.
[10] Yilmaz O., Celik H., 2003, Electrical and thermal properties of the interface at diffusion-bonded and soldered 304 stainless steel and copper bimetal, Journal of Materials Processing Technology 141(1): 67-76.
[11] Kumar A. M., Hakeem S. A., 2000, Optimum design of symmetric composite patch repair to centre cracked metallic sheet, Composite Structures 49(3): 285-292.
[12] Brighenti R., 2007, Patch repair design optimisation for fracture and fatigue improvements of cracked plates, International Journal of Solids and Structures 44(3-4): 1115-1131.
[13] Okafor A.C., Singh N., Enemuoh U.E., Rao S.V., 2005, Design, analysis and performance of adhesively bonded composite patch repair of cracked aluminum aircraft panels, Composite Structures 71(2): 258-270.
[14] Albedah A., Bouiadjra B. B., Mhamdia R., Benyahia F., Es-Saheb M., 2011, Comparison between double and single sided bonded composite repair with circular shape, Materials & Design 32(2): 996-1000.
[15] Mahendran G., Babu S., Balasubramanian V., 2010, Analyzing the effect of diffusion bonding process parameters on bond characteristics of Mg-Al dissimilar joints, Journal of Materials Engineering and Performance 19(5): 657-665.
[16] Kurt B., Orhan N., Evin E., Çalik A., 2007, Diffusion bonding between Ti–6Al–4V alloy and ferritic stainless steel, Materials Letters 61(8-9): 1747-1750.
[17] Wei Y., Aiping W., Guisheng Z., Jialie R., 2008, Formation process of the bonding joint in Ti/Al diffusion bonding, Materials Science and Engineering A 480(1-2): 456-463.
[18] Kenevisi M.S., Khoie S.M., 2012, A study on the effect of bonding time on the properties of Al7075 to Ti–6Al–4V diffusion bonded joint, Materials Letters 76: 144-146.
[19] Chen H., Cao J., Tian X., Li R., Feng J., 2013, Low-temperature diffusion bonding of pure aluminum, Applied Physics A 113(1): 101-104.‏
[20] Kumar S., Kumar P., Shan H.S., 2007, Effect of evaporative pattern casting process parameters on the surface roughness of Al–7% Si alloy castings, Journal of Materials Processing Technology 182(1-3): 615-623.
[21] Mahendran G., Balasubramanian V., Senthilvelan T, 2009, Developing diffusion bonding windows for joining AZ31B magnesium–AA2024 aluminium alloys, Materials & Design 30(4): 1240-1244.
[22] Dehghanpour S., Nezamabadi A., Attar M., Barati F., Tajdari M, 2019, Repairing cracked aluminum plates by aluminum patch using diffusion method, Journal of Mechanical Science and Technology 33(10): 4735-4743.
[23] Ismail A., Hussain P., Mustapha M., Nuruddin M.F., Saat A.M., Abdullah A., Chevalier S., 2016, Fe-Al diffusion bonding: effect of reaction time on the interlayer thickness, Journal of Mechanical Engineering 13(2): 10-20.
[24] Montgomery D.C., 2017, Design and Analysis of Experiments, John Wiley & Sons.
[25] Jafarian M., Paidar M., 2016, The comparison of microstructure and mechanical properties of diffusion joints of 5754, 6061, and 7039 aluminum alloys to AZ31 magnesium alloy, Journal of Advanced Materials in Engineering 35(1): 11-21.
[26] Fernandus M.J., Senthilkumar T., Balasubramanian V., 2011, Developing temperature–time and pressure–time diagrams for diffusion bonding AZ80 magnesium and AA6061 aluminium alloys, Materials & Design 32(3): 1651-1656.‏
[27] Fernandus M.J., Senthilkumar T., Balasubramanian V., Rajakumar S., 2012, Optimising diffusion bonding parameters to maximize the strength of AA6061 aluminium and AZ31B magnesium alloy joints, Materials & Design 33: 31-41.
[28] Kundu S., Chatterjee S., 2008, Characterization of diffusion bonded joint between titanium and 304 stainless steel using a Ni interlayer, Materials Characterization 59(5): 631-637.