STP1165

    In Search of Microstructure

    Published: Jan 1993


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    Abstract

    When metals were discovered over 8000 years ago, there was no scientific basis for understanding their properties. Although metal production and working were developed by trial and error, skills were developed that produced amazing works of art and utility. Based upon surface evidence, Renaissance philosophers and alchemists speculated that metals possessed a discrete internal structure. It was not until the mid-nineteenth century that Henry Sorby developed the first successful method of revealing the microstructure of metals and alloys. From this beginning, the search for microstructure was aided by new developments such as synthetic abrasives and improved equipment. With each new wave of alloy development, metallographers modified the simple technique developed by Sorby to accommodate the new materials. Cemented carbides, super alloys, and nuclear materials were challenges that were overcome by adapting traditional metallography. However, when traditional metallography was applied to the most recently developed advanced materials such as fine ceramics, composites, and thermally sprayed coatings, it was apparent that a new direction was needed. Using a combination of fixed, semifixed, and free abrasives, and a graded series of lapping platens and cloths, a three-stage system has been developed that is capable of solving the challenges represented by the new wave of advanced materials.

    Keywords:

    metals, metallurgy, metallography, microstructure, advanced materials, fine ceramics, composites, thermally sprayed coatings, lapping, deformation, polishing, abrasives, metallurgical specimens, metallographic techniques


    Author Information:

    Nelson, JA
    Manager, Educational Services, Buehler, Ltd., Lake Bluff, IL


    Paper ID: STP25110S

    Committee/Subcommittee: E04.11

    DOI: 10.1520/STP25110S


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