Contents lists available at ScienceDirect Materials Characterization journal homepage: www.elsevier.com/locate/matchar Residual stresses distribution, correlated with bending tests, within explosively welded Ti gr. 2/A1050 bimetals D.M. Fronczek a, ⁎ , K. Saksl b,c , R. Chulist a , S. Michalik d , J. Wojewoda-Budka a , L. Sniezek e , M. Wachowski e , J. Torzewski e , M. Sulikova c , K. Sulova b,f , A. Lachova c , M. Fejercak b,c , D. Daisenberger e , Z. Szulc g , Z. Kania a a Institute of Metallurgy and Materials Science Polish Academy of Sciences, 25 Reymonta Street, 30-059 Cracow, Poland b Institute of Materials Research, Slovak Academy of Sciences, Watsonova 47, 040 01 Košice, Slovak Republic c Faculty of Sciences, Institute of Physics, Univerzita Pavla Jozefa Šafárika v Košiciach, Šrobárova 1014/2, Košice 041 80, Slovak Republic d Diamond Light Source Ltd., Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, UK e Faculty of Mechanical Engineering, Military University of Technology, 2 Urbanowicza Street, 01-476 Warsaw, Poland f Faculty of Materials Metallurgy and Recycling, Technical University of Košice, Letna 9, 042 00 Košice, Slovak Republic g High Energy Technologies Works ‘Explomet’, 100H Oswiecimska Street, 45-641 Opole, Poland ARTICLE INFO Keywords: Explosive welding Aluminum Titanium Bending SEM/EBSD Residual stress ABSTRACT Synchrotron radiation and XRD 2 method were used to investigate the residual stress distribution before and after three point bending tests within an explosively welded composite composed of two light metals, namely: Ti gr. 2 and A1050. The analysis has shown that the bimetal is slightly affected by the explosive welding process since negative sign values of stress tensor were detected only in the immediate vicinity of interface of Ti gr. 2 char- acterized by a width of about 0.25 mm. Upon bending higher negative compression stresses are detected in this area as the σ 11 value changes from -500 MPa to -1200 MPa. Additionally, the analysis of microstructure has revealed significant changes in twins morphology with primary and conjugate twinning before and after bending, respectively. However, the compressive twinning was the dominant system in both cases. Bending has changed the initial bimodal texture developing more spread basal components towards the transverse direction. The sample surface has been also significantly affected as the presence of compressive residual stress (-500 MPa) after bending was measured. 1. Introduction In recent years detailed study of technological parameters and de- velopment of ‘welding window’ diagrams [1–6] succeeded in joining of various bimetals such as W/Cu [3], Inconel 625/steel [5], Ti/Al [7,8], Ti/steel [9] or steel/stainless steel [10] and multilayered materials e.g. Ti/Al [11–14], Al/Mg [15], Al/Cu [16] or Ni/Al [4] by an explosive welding (EXW) method. However, as in the case of other welding processes such as friction stir welding [17], gas tungsten arc welding [18] or electron beam welding [19], residual stresses are observed after EXW [20–29]. The residual stresses evolve within ingoing metals due to temperature gradients observed at the bonding surface and much lower within the clads [28,30,31]. Through-depth residual stress can be ob- served within composites manufactured by EXW due to different linear expansion coefficients of each element [23,32]. Depending on stress distribution and their interaction with external forces, they can influ- ence both the mechanical properties and lifetime (e.g. compressive residual stresses can delay fatigue cracking or induce plastic deforma- tion) [33]. In other words, residual stresses are one of the key para- meters determining the structural and functional properties of the materials. They may affect the composites integrity, thus a compre- hensive study of the residual stresses profile is of great interest. There are few reports concerning the problem of residual stress distribution within explosively welded metals, where various measuring methods https://doi.org/10.1016/j.matchar.2018.08.004 Received 23 May 2018; Received in revised form 1 August 2018; Accepted 1 August 2018 ⁎ Corresponding author. E-mail addresses: d.fronczek@gmail.com (D.M. Fronczek), ksaksl@imr.saske.sk (K. Saksl), r.chulist@imim.pl (R. Chulist), stefan.michalik@diamond.ac.uk (S. Michalik), j.wojewoda@imim.pl (J. Wojewoda-Budka), lucjan.sniezek@wat.edu.pl (L. Sniezek), marcin.wachowski@wat.edu.pl (M. Wachowski), janusz.torzewski@wat.edu.pl (J. Torzewski), michaela.sulikova1@studen.upjs.sk (M. Sulikova), ksulova@saske.sk (K. Sulova), lachova.ada@gmail.com (A. Lachova), milos.fejercak@gmail.com (M. Fejercak), dominik.daisenberger@diamond.ac.uk (D. Daisenberger), zszulc@op.onet.pl (Z. Szulc), z.kania@imim.pl (Z. Kania). Materials Characterization 144 (2018) 461–468 Available online 02 August 2018 1044-5803/ © 2018 Elsevier Inc. All rights reserved. T