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EPNM2014-Kraków. PHASE ANALYSIS EXPLOSIVE WELDED Ti-Cr/Ni STEEL IN AS-RECEIVED STATE AND AFTER HEAT TREATMENT USING SYNCHROTRON. Dmytro OSTROUSHKO a , Eva MAZANCOVÁ a , Karel SAKSL b , Ondrej Milkovič b. EPNM2014-Kraków. A im.
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EPNM2014-Kraków PHASE ANALYSIS EXPLOSIVE WELDED Ti-Cr/Ni STEEL IN AS-RECEIVED STATE AND AFTER HEAT TREATMENT USING SYNCHROTRON Dmytro OSTROUSHKO a, Eva MAZANCOVÁ a, Karel SAKSL b, OndrejMilkovičb
EPNM2014-Kraków Aim • The work is focused on interface shape line, inhomogeneities in vicinity of the wave joint both in basic material and in vicinity of weld line of the Ti and Cr/Ni stainless steel (SS) matrix. • Investigated weld was both in as-received state and after heat treatment carried out at 600°C/90 minutes/air. • Presented phases have been identified using X-ray diffraction performed by synchrotron. The Ti, Fe-fcc, Fe-bcc and intermetallic phases Fe2Ti were detected at interface area.
EPNM2014-Kraków Experimental material In collaboration with the company EXPLOMET the following materials were joined Ti + SS, thisbimetal consists of pure α-Ti and 18/10 Cr/Ni steel with high strength and excellent corrosion resistance. Primarily used in heavy chemical industry. Preparation of samples to phase analysis - Embedded – Polyfast, Isofast - Grinded – P300, P600, P800, P1200, P2500 - Polished 0.006 mm + H2O(PHOENIX 4000, Buehler) - Etched – KROLL (100ml H2O+ 6ml HNO3 + 3ml HF) time was about 3 second.
EPNM2014-Kraków Bonding line of Ti-Cr/Ni SS sandwich Typical bonding line (interface) of the studied material figures demonstrates. After the HT Ti-Cr/Ni SS sandwich shows wavy interface in nature as it was observed after explosive bonding Typical wavy bonding zone Ti-Cr/Ni steelwithout etching Ti Interface SS Typical wavy bonding zone Ti-Cr/Ni steelafter etching
EPNM2014-Kraków Synchrotron (BW-5)DORIS III XRD measurements were carried out using the BW5 experimental station located at the DORIS III positron storage ring (energy 4.45 GeV, current 140–100 mA) at HASYLAB/DESY, Hamburg, Germany. The energy of the incident beam was 100 keV, lambda=0.124 Å.
EPNM2014-Kraków Synchrotron (BW-5) DORIS III The specimen was scanned shot-by-shot along a path of total length 40 mm with step width of 1mm. During each step, the sample was illuminated by highly intensive hard X-rays for 2 seconds. The resulting 2D XRD patterns were recorded using a Perkin Elmer 1621 detector. The collected data were then integrated into 2 Theta space using the FIT2D software. Thesample-detector distance, detector orthogonality with respect to the incoming radiation, as well as precise radiation energy were determined by fitting a standard reference LaB6 sample.
EPNM2014-Kraków Synchrotron (BW-5) DORIS III 3D plot of obtained XRD patterns taken shot-by-shot going from the SS to Ti. The picture clearly indicates abrupt change of theXRD pattern corresponding to interface between this two materials.
EPNM2014-Kraków Synchrotron (BW-5) DORIS III XRD pattern from the interface region is shown together with patterns taken CCA 1 cm away from the interface in both direction. Ti consists of sole hcp-Ti alpha phase and the SS of fcc-Fe phase solid solution and bcc-Fe like phases. There are differences in the proportion of bcc-Fe in comparison with the sample withthe HT which show their significantly lower level (approximately by 60% - diffraction maxima for images with "o"). Other intermetallic phases haven't been detected by this method.
EPNM2014-Kraków Synchrotron (P-07)PETRA III The second X-ray micro-diffraction experiment was performed at beamline P07at PETRA III (positron storage ring operating at energy 6GeV with beam current 100mA). During the experiment, monochromatic synchrotron radiation of energy 80.09keV (λ = 0.01548nm) was used.
EPNM2014-Kraków Synchrotron (P-07)PETRA III The beam of photons was focused by compound refractive lenses down to a spot size of 2.2μm x 34μm. The specimen was scanned shot-by-shot along a straight path of total length 0,4 mm with step width of 1µm. During each step, the sample was illuminated by highly intensive hard X-rays for 0.5 seconds. The resulting 2D XRD patterns were recorded using a Perkin Elmer 1621 detector. The intensity was integrated to 2 Theta space by using the Fit2D software.
EPNM2014-Kraków Synchrotron (P-07)PETRA III Phase analysis from the interfacial region proved existence of the hexagonal close packed Fe2Ti intermetallic phase together with main matrix components fcc-Fe (austenite) and bcc-Fe (ferrite). Comparison between explosion welded (as-received) and the sample after HT testify effective reduction of intermetallic compound by the annealing. Volume percentage Fe2Ti in the as-prepared sample is about 17.5% while after the HT is approx. by 70% less (5.25 vol. %).
EPNM2014-Kraków Synchrotron (P-07)PETRA III In addition, we quantify the amount of intermetallic phase measuring from centre of the interface to both materials. The phase is visible in region wide approx. 204 m and for the annealed sample is significantly lover compared to the as-received state. The measurement proved that the HT is effective procedure to dissolute unwanted intermetallic compound and to improve the whole material lifetime.
EPNM2014-Kraków CONSLUSIONS • The first XRD pattern showed that the interface region of both the samples probed in area 1x1 mm consist of the hcp-Ti, fcc-Fe solid solution and bcc-Fe like phases. The sample after annealing at 600 °C/90 min./air shows significantly lower amount of the bcc-Fe phase. Other intermetallic phases were not detected by synchrotron (BW5). • The second experiment proved existence of the hexagonal close packed Fe2Ti intermetallic phase together with main matrix components fcc Fe (austenite) and bcc-Fe (ferrite). In order to quantify volume amount of intermetallic phase in the samples we performed Rietveld refinement of the XRD patterns. Volume percentage Fe2Ti in the as-prepared sample is about 17.5% while after the HT is ~70% less (5.25 vol.%). The measurement proved that the HT is effective procedure to dissolution unwanted intermetallic compound causing improvement of the whole material lifetime. • In future works it would be useful presented results to verify using other explosively welded samples.
EPNM2014-Kraków ACKNOWLEDGEMENT This paper was created within the project 7AMB14SK023“Mobilities“, 02613/2013/RRC „InternationalResearchTeams“ sponsored by NorthernMoravian region, withintheproject SP 2014/62 “SpecificResearch in Metallurgical, MaterialandProcessEngineering“ and No. L01203 L “RegionalMaterials Science and Technology Centre – Feasibility Program“ founded by Ministry ofEducation, YoungandSportsofCzechRepublic. Specialthanksbelongs to EXPLOMET foranimportantcooperation.
EPNM2014-Kraków THANKS FOR YOUR ATTENTION Slovak Academy of Sciences Institute of Material Research Kosice, Slovakia