Diffraction Research in Engineering and Advanced Materials

Current Research Projects include:

• Synchrotron X-ray radiation for strain scanning for engineering applications using  (Funding: ESRF, EU TMR)
• Self-consistent modelling and diffraction study of bcc and hcp polycrystals (Funding: EPSRC)
• Internal stress evaluation using multiple peak laboratory X-ray diffraction analysis (Funding: Oxford, EPSRC)
• Residual stress effects on deformation behaviour of metal matrix composites
• Design of coatings and coated systems (Funding: EPSRC)
• Indentation of coated systems (Funding: Royal Society)

Synchrotron particle acceleration is an excellent way to produce some high energy X-rays.

The basics of synchrotron light generation are explained in Alexander's short note on the subject.

We use synchrotron beamlines at the SRS Daresbury Laboratory and the European Synchrotron Radiation Facility, ESRF, in Grenoble.

Examples of detailed experimental strain mapping are shown in the figures below: (a) a region near the end of a TIG weld pass in an Al alloy plate, and (b) strain intensification around a crack traversing a four-point bent bar.

(a) (b) 

Laboratory surface X-ray Diffraction

Laboratory X-ray diffraction is an important tool for phase, texture and stress characterisation in a variety of practically important situations. The photograph shows one of the panels from the fuselage of Russian Tupolev-154 civil aircraft, which were removed during refurbishment after 11, 15 and 20 years of service. We considered the degradation of strength due to a combination of corrosion and fatigue in a study which drew on unique data obtained from coupons. Along with electrochemical properties, residual stresses, peak broadening and polar density variation of different reflections were considered as a function of depth, number of flights, and time of service. A new view was developed of the chemical/structural interactions during combined corrosion and fatigue.
 

Neutron Diffraction

(AM Korsunsky et al @ ISIS, RAL)

The combination of highly penetrating white neutron beam and the servohydraulic INSTRON loading rig on ENGIN allowed us to carry out in situ fully reversed fatigue cycling experiments. Our aim was to inivestigate the difference in the cyclic response of differently oriented groups of grains. The figure clearly demonstrates the importance of such insight for design against failure: while the 111 trace is given by a virtually straight line, the 200 shows significant deviation from linearity, caused by large plastic strain experienced by these grains.
 

Selected publications:
 

• Korsunsky A.M., Salimon A.I., Pape I., Polyakov A.M., Fitch A.N. The thermal expansion coefficient of mechanically alloyed Al-Cu-Fe quasicrystalline powders, Scripta Mater., v. 44, p. 217–222, 2001. 

• Salimon A.I., Korsunsky A.M., Kaloshkin S.D., Tcherdyntsev V.V., Shelekhov E.V., Sviridova T.A., The evolution of crystalline precursors during the formation of Al-Cu-Fe quasicrystalline intermetallics in mechanically alloyed powders, presented at ISMANAM2000, Oxford; to appear in the J. Non-Cryst. Solids. 

• Korsunsky A.M., Daymond M.R. and Wells K.E., The Development of Strain Anisotropy during Plastic Deformation of an Aluminium Polycrystal, Materials Science Forum v. 347-349, p. 492-497, 2000. 

• Korsunsky A.M., Wells K.E. and Shaw B.A., A Comparative Study of Diffraction Methods for Strain Measurement in a Particulate MMC, Materials Science Forum v. 347-349, p. 504-509, 2000.

• Salimon A.I., Korsunsky A.M., Shelekhov E.V., Sviridova T.A., Preparation and Analysis of Quasicrystalline Phases by High Energy Ball Milling and X-Ray Diffraction. Materials Science Forum v. 321-324, p. 676-681, 2000.

• Korsunsky A.M., Wells K.E., High Energy Synchrotron X-Ray Measurements of 2D Residual Stress States in Metal Matrix Composites. Materials Science Forum v. 321-324, p. 218-223, 2000.

• Salimon AI, Korsunsky AM, Ivanov AN, The character of dislocation structure evolution in nanocrystalline FCCNi-Co alloys prepared by high-energy mechanical milling, MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, v.271,p.196-205, 1999. 

• Wells K.E., Korsunsky A.M., Strain analysis in composites using synchrotron X-ray diffraction, EXPERIMENTAL MECHANICS, VOLS 1 AND 2, 1998, Ch. 219, pp.761-766 ADVANCES IN DESIGN, TESTING AND ANALYSIS.

• Korsunsky A.M., Wells K.E, Withers P.J., Mapping two-dimensional state of strain using synchroton X-ray diffraction, SCRIPTA MATERIALIA, 1998, Vol.39, No.12, pp.1705-1712. 

• Korsunsky A.M. and Withers P.J., Investigation of residual stress induced crack closure and its effects on fatigue in metal matrix composites, Key Engineering Materials, vols. 127-131, p. 1183-1190, 1997. 

• Korsunsky A.M., Residual stress evolution in a metal matrix composite subjected to plastic bending, in T. Ericsson, Ed., Proc. 5th Intl. Conf. on Residual Stresses (ICRS-5), Linkoping, Sweden, 16-18 June, 1997.

• Watts M.R., Withers P.J., Korsunsky A.M. and Fitzpatrick M.E., X-ray and neutron diffraction measurement of micro and macrostresses in metal matrix composites, in Proc. ECRS4, Cluny-en-Bourgogne, May 1996.

• Korsunsky A.M., Fitzpatrick M.E., and Withers P.J., Neutron diffraction measurement and modelling of stresses around fatigue cracks in Al/SiC composites, in Proceedings of the Tenth Intl. Conf. on Composite Materials (ICCM-10), A.Poursartip and K.Street, eds., Whistler B.C., Canada, 14-18 August, 1995, vol.1, pp.545-552.

You can download a pdf copy of references showing the pdf logo .