Microstructural characterisation of rotary friction welded AA6082 and Ti-6Al-4V dissimilar joints

Abstract The aim of this work was to investigate the weld interface and microstructure of a rotary friction welded (RFW) Ti-6Al-4V to AA6082 joint for the purpose of future spacecraft applications. A recent initiative by the European Space Agency (contract No. 4000111471/14/NL/PA) towards a more sustainable materials and processes selection has given the development of advanced joining techniques significant momentum. As part of this strategic development, it was proposed to produce propellant and pressurant tanks with aluminum alloys, joined to the Ti-6Al-4V tubing and pipework surrounding the tank with advanced joining methods. Consequently, Omnidea-RTG and IWS were tasked to develop the joining of dissimilar, tube and rod shaped materials via rotary friction welding, a solid-state welding technique. Thorough parameter optimisation of the welding process has resulted in consistent and reliable welds with excellent mechanical properties. Nonetheless, due to the complex kinetics of the RFW process, the potential formation of brittle intermetallic compounds at the weld interface is still a possibility. Therefore, the microstructure of rotary friction welded AA6082 and Ti-6Al-4V joints was investigated. Emphasis was placed on the detailed inspection of the weld interface and the surrounding base alloys, as well as the compositional evolution throughout the interface region.

[1]  K. Ameyama,et al.  Influence of silicon in aluminium on the mechanical properties of titanium/aluminium friction joints , 1995, Journal of Materials Science.

[2]  Han-Sur Bang,et al.  Interfacial Microstructure and Mechanical Properties of Dissimilar Friction Stir Welds between 6061-T6 Aluminum and Ti-6%Al-4%V Alloys * , 2011 .

[3]  A. Wu,et al.  Interface and properties of the friction stir welded joints of titanium alloy Ti6Al4V with aluminum alloy 6061 , 2015 .

[4]  G. Madhusudhan Reddy,et al.  Friction welding of dissimilar pure metals , 2007 .

[5]  Xiaoyan Zeng,et al.  Effect of Weld Characteristic on Mechanical Strength of Laser-Arc Hybrid-Welded Al-Mg-Si-Mn Aluminum Alloy , 2016, Metallurgical and Materials Transactions A.

[6]  M. Horstmann,et al.  Improving interfacial properties of a laser beam welded dissimilar joint of aluminium AA6056 and titanium Ti6Al4V for aeronautical applications , 2010 .

[7]  M. Ohno,et al.  On the kinetics of TiAl3 intermetallic layer formation in the titanium and aluminum diffusion couple , 2013 .

[8]  N. Ryum,et al.  Precipitation of dispersoids containing Mn and/or Cr in Al-Mg-Si-alloys , 2000 .

[9]  Sergio Lozano-Perez,et al.  A guide on FIB preparation of samples containing stress corrosion crack tips for TEM and atom-probe analysis. , 2008, Micron.

[10]  Y. Chen,et al.  Microstructural characterization and mechanical properties in friction stir welding of aluminum and titanium dissimilar alloys , 2009 .

[11]  F. Froes,et al.  Joining similar and dissimilar advanced engineered materials , 1995 .

[12]  L. Shreir,et al.  The nature and growth of interaction layers formed during the reaction between solid titanium and liquid aluminium , 1959 .

[13]  Joseph D. Robson,et al.  Microstructural characterization and mechanical properties of high power ultrasonic spot welded aluminum alloy AA6111–TiAl6V4 dissimilar joints , 2014 .

[14]  G. Biallas,et al.  Friction stir welding of titanium alloy TiAl6V4 to aluminium alloy AA2024-T3 , 2009 .

[15]  Y. C. Kim,et al.  Factors dominating joint characteristics in Ti – Al friction welds , 2002 .

[16]  N. Alcântara,et al.  Interface formation and properties of friction spot welded joints of AA5754 and Ti6Al4V alloys , 2016 .

[17]  S. Sangal,et al.  On the formation of TiAl3 during reaction between solid Ti and liquid Al , 1997 .

[18]  K. E. Nilsen,et al.  The dependence of the β-AlFeSi to α-Al(FeMn)Si transformation kinetics in Al–Mg–Si alloys on the alloying elements , 2005 .

[19]  V. L. Acoff,et al.  Interfacial reactions of titanium and aluminum during diffusion welding , 2000 .

[20]  Wenya Li,et al.  Linear and rotary friction welding review , 2016 .

[21]  Xiaoyan Zeng,et al.  Microstructure and Tensile Behavior of Laser Arc Hybrid Welded Dissimilar Al and Ti Alloys , 2014, Materials.

[22]  Fred J. Vermolen,et al.  A Model of the β-AlFeSi to α-Al(FeMn)Si Transformation in Al-Mg-Si Alloys , 2003 .

[23]  N. Kuijpers,et al.  Quantification of the evolution of the 3D intermetallic structure in a 6005A aluminium alloy during a homogenisation treatment , 2002 .

[24]  S. Nakamura,et al.  Mechanical properties of friction welded joint between Ti–6Al–4V alloy and Al–Mg alloy (AA5052) , 2005 .

[25]  Gd Gerard Rieck,et al.  Diffusion in the titanium-aluminum system. I. Interdiffusion between solid aluminum and titanium or titanium-aluminum alloys , 1973 .

[26]  Sung-Hwan Lim,et al.  Microstructural evaluation of interfacial intermetallic compounds in Cu wire bonding with Al and Au pads , 2014 .

[27]  R. K. Nahar,et al.  Effect of Si on the reaction kinetics of Ti/AlSi bilayer structures , 1987 .

[28]  N. Kuijpers,et al.  Characterization of the α-Al(FeMn)Si nuclei on β-AlFeSi intermetallics by laser scanning confocal microscopy , 2003 .