Journals / CMC / Vol.14, No.3
Table of Content


    Identification of Particle Stimulated Nucleation during Recrystallization of AA 7050

    D.P. Field1, L. Behrens2, J.M. Root1
    CMC-Computers, Materials & Continua, Vol.14, No.3, pp. 171-184, 2009, DOI:10.3970/cmc.2009.014.171
    Abstract Mechanical properties of polycrystalline metals are dependent upon the arrangement of microstructural features in the metal. Recrystallization is an important phenomenon that often occurs during thermo-mechanical processing of metals. This work focuses upon aluminum alloy 7050 and uses crystallographic texture and pair correlation functions of recrystallized grains to characterize the dominance of particle stimulated nucleation in the recrystallization process. The randomization of the recrystallization texture and similar pair correlation functions for the particle distribution and the recrystallization nuclei distribution indicate that particle stimulated nucleation controls the recrystallization behavior in this alloy. More >


    EBSD-Based Microscopy: Resolution of Dislocation Density

    Brent L. Adams, Joshua Kacher
    CMC-Computers, Materials & Continua, Vol.14, No.3, pp. 185-196, 2009, DOI:10.3970/cmc.2009.014.185
    Abstract Consideration is given to the resolution of dislocation density afforded by EBSD-based scanning electron microscopy. Comparison between the conventional Hough- and the emerging high-resolution cross-correlation-based approaches is made. It is illustrated that considerable care must be exercised in selecting a step size (Burger's circuit size) for experimental measurements. Important variables affecting this selection include the dislocation density and the physical size and density of dislocation dipole and multi-pole components of the structure. It is also illustrated that simulations can be useful to the interpretation of experimental recoveries. More >


    Measurements of the Curvature of Protrusions/Retrusions on Migrating Recrystallization Boundaries

    Y.B. Zhang1, A. Godfrey2, D. Juul Jensen1
    CMC-Computers, Materials & Continua, Vol.14, No.3, pp. 197-208, 2009, DOI:10.3970/cmc.2009.014.197
    Abstract Two methods to quantify protrusions/retrusions and to estimate local boundary curvature from sample plane sections are proposed. The methods are used to evaluate the driving force due to curvature of the protrusions/retrusions for partially recrystallized pure nickel cold rolled to 96% reduction in thickness. The results reveal that the values calculated by both these methods are reasonable when compared with the stored energy measured by differential scanning calorimetry. The relationship between protrusions and the average stored energy density in the deformed matrix is also investigated for partially recrystallized pure aluminum cold rolled to 50%. The results show that the local… More >


    Statistics of High Purity Nickel Microstructure From High Energy X-ray Diffraction Microscopy

    C.M. Hefferan1, S.F. Li1, J. Lind1, U. Lienert2, A.D. Rollett3, P. Wynblatt3, R.M. Suter1,3
    CMC-Computers, Materials & Continua, Vol.14, No.3, pp. 209-220, 2009, DOI:10.3970/cmc.2009.014.209
    Abstract We have measured and reconstructed via forward modeling a small volume of microstructure of high purity, well annealed nickel using high energy x-ray diffraction microscopy (HEDM). Statistical distributions characterizing grain orientations, intra-granular misorientations, and nearest neighbor grain misorientations are extracted. Results are consistent with recent electron backscatter diffraction measurements. Peaks in the grain neighbor misorientation angle distribution at 60 degrees (∑3) and 39 degrees (∑9) have resolution limited widths of ≈ 0.14 degree FWHM. The analysis demonstrates that HEDM can recover grain and grain boundary statistics comparable to OIM volume measurements; more extensive data sets will lead to full, five… More >

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