Journal of Materials Physics and Chemistry
ISSN (Print): 2333-4436 ISSN (Online): 2333-4444 Website: http://www.sciepub.com/journal/jmpc Editor-in-chief: Dr. A. Heidari
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Journal of Materials Physics and Chemistry. 2013, 1(4), 58-64
DOI: 10.12691/jmpc-1-4-1
Open AccessArticle

Time-evolution of Heat Affected Zone (HAZ) of Friction Stir Welds of AA7075-T651

A. Pastor1 and H. G. Svoboda2,

1Sabato Institute, UNSAM/CNEA, San Martín, Argentina

2Materials and Structures Laboratory, INTECIN, Faculty of Engineering, University of Buenos Aires, Buenos Aires, Argentina

Pub. Date: November 06, 2013

Cite this paper:
A. Pastor and H. G. Svoboda. Time-evolution of Heat Affected Zone (HAZ) of Friction Stir Welds of AA7075-T651. Journal of Materials Physics and Chemistry. 2013; 1(4):58-64. doi: 10.12691/jmpc-1-4-1

Abstract

Friction Stir Welding (FSW) is a novel solid-phase welding process, which has proved to have a great potential for the realization of welded joints in materials with poor weldability such as heat-treatable aluminum alloys. However, the thermal cycles generated during FSW change the mechanical properties in heat affected zone (HAZ) due to two effects: over-age and re-dissolution of hardening precipitates. In other hand, the re-dissolved precipitates produce a evolution of both the microstructure and mechanical properties due to the natural aging phenomenon. The aim of this paper was to analyze the microstructural evolution in the HAZ of FSW joints in AA7075-T651 alloy. For this purpose samples FSW welded butt plate 4 mm in thickness. On the welded joint microstructural characterization was performed by light microscopy (LM), X-ray diffraction (XRD) and differential scanning calorimetry (DSC) and Vickers microhardness profiles (HV) after different elapsed times post welding. It was observed that the hardness increases with time after welding, due to the evolution of the phases present.

Keywords:
friction stir welding (FSW) AA7075-T651 heat affected zone (HAZ) differential scanning calorimetry (DSC)

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References:

[1]  American Society for Metals (ASM). Properties and Selection: Nonferrous Alloys and Special-Purpose Materials (Vol. 2). 10 ma ed. Ohio: ASM International. 2005.
 
[2]  J. Gilbert Kaufman “Introduction to Aluminum Alloys and Tempers”, 2000, ASM International.
 
[3]  J. R. Kissell and R. L. Ferry, “Aluminum Structures: A guide to their specifications and design”, 2002, John Wiley and Sons, Inc.
 
[4]  D.A. Porther, K.E. Easterling. “Phase transformation in metals and alloys”, 1992, Chapman & Hall.
 
[5]  R.S. Mishra and Z.Y. Ma, “Friction stir welding and processing”. Materials Science and Engineering R, Vol. 50 (2005), p. 1-78.
 
[6]  R. Nandan, T. DebRoy, H.K.D.H Bhadeshia. “Recent advances in friction-stir welding – Process, weldment structure and properties”, Progress in Materials Science, Vol 53 (2008), p. 980-1023.
 
[7]  W. Xu, J. Liu, G. Luan, C. Dong, “Microstructure and mechanical properties of friction stir welded joints in 2219-T6 aluminum alloy”, Materials and Design, Vol. 30 (2009), p. 3460-3467.
 
[8]  J.Q. Su, T.W. Nelson, R.S. Mishra, M.W. Mahoney. “Microstructural investigation of friction stir welded 7050-T651 aluminum”, Acta Materialia, Vol 51 (2005), p. 713-718.
 
[9]  K.V. Jata, K.K. Sankaran, J.J. Ruschau. “Friction stir welding effects on microstructure and fatigue of aluminum alloy 7050-T7451”, Metallic Materials Transaction. A. Vol. 31 (2000), p. 2181-2187.
 
[10]  C. B. Fuller, M. W. Mahoney, M. Calabrese, L. Micona. “Evolution of microstructure and mechanical properties in naturally aged 7050 and 7075 Al friction stir welds”, Materials Science and Engineering A. Vol 527 (2010), p. 2233-2240.
 
[11]  J.K. Park, A.J. Ardell. “Correlation between Microstructure and Calorimetric Behavior of Aluminum Alloy 7075 and AI-Zn-Mg Alloys in Various Tempers”, Materials Science and Engineering A, Vol. 114 (1989), p. 197-203.
 
[12]  L. N. Tufaro. “Tensiones Residuales y Propiedades Mecánicas de uniones Soldadas por Fricción-Agitación (FSW) de AA 7075-T651”, Buenos Aires, Facultad de Ingeniería UBA, 2012.
 
[13]  F. Viana, A.M.P. Pinto, H.M.C. Santos, A.B. Lopes. “Retrogression and re-ageing of 7075 aluminum alloy: microstructural characterization”, Journal of Materials Processing Technology, Vol 92-93 (1999), p. 54-59
 
[14]  A. Baldantoni. “On the microstructural changes during the retrogression and re-aging of 7075 type aluminum alloys”. Materials Science Engineering. Vol 72: L5- L8. 527 (1985), p. 2233-2240.
 
[15]  J.M. Papazian. “Differential Scanning Calorimetry Evaluation of Retrogressed and Re-aged Microstructures in Aluminum Alloy 7075”. Materials Science Engineering 79 (1986), p. 97-104.
 
[16]  A. E. Pastor. “Efecto de las variables del proceso de Soldadura por Fricción Agitación (FSW) de aleaciones de aluminio de alta resistencia sobre la microestructura y las propiedades mecánicas”, Buenos Aires, Instituto de Tecnología Jorge Sabato, 2012.
 
[17]  M. Ku, F. Hung, T. Lui and L. Chen, “Embrittlement Mechanism on Tensile Fracture of 7075 Al Alloy with Friction Stir Process (FSP)”, Materials Transactions, Vol. 52, No. 1 (2011), pp. 112 to 117.