Mechanical attrition and mechanical alloying have been developed as a versatile alternative to other processing routes in preparing nanophase powder materials with a broad range of chemical compositions and atomic structures. This internal refining process results in a reduction of the average grain size to nanometer scales by the creation and self-organization of small-angle and high-angle grain boundaries within the powder particles. Similar observations have been made on heavily worn surfaces. Due to the large shear stresses at the rail/wheel contact area of high speed trains, a transformation of the pearlitic steel to a nanocrystalline state and the dissolution of carbides is observed. As a consequence, the microhardness is increased by a factor of five corresponding to about 12 GPa. This non-equilibrium material favors the development of corrugations causing considerable acoustic noise and the formation of microcracks leading to a steady devastation of the rail as well as the wheel. A comparison is being made between the physical properties of the nanostructured surface layers of the rail, ball milled powder particles and severely plastically deformed bulk samples with identical composition.


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    Titel :

    Nanostructure formation and mechanical alloying in the wheel / rail contact area of high speed trains in comparison with other synthesis routes


    Beteiligte:
    Djahanbakhsh, M. (Autor:in) / Lojkowski, W. (Autor:in) / Burkle, G. (Autor:in) / Baumann, G. (Autor:in) / Ivanisenko, Y.V. (Autor:in) / Valiev, R.Z. (Autor:in) / Fecht, H.J. (Autor:in)


    Erscheinungsdatum :

    2001


    Format / Umfang :

    8 Seiten, 32 Quellen




    Medientyp :

    Aufsatz (Konferenz)


    Format :

    Print


    Sprache :

    Englisch