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  • 1.  Tungsten Rhenium Grain Boundaries

    Posted 6 days ago
      |   view attached
    Hello everyone, 

    I came to the forum today to ask about etching Tungsten Rhenium. I have been etching Tungsten Rhenium 3% needles to look at the grain boundaries of the needles. It was clear that the boundaries were aligned in the direction of the needle and curved around the 90 degree bend in the needle. I decided to bend the needle to 180 degrees and etch the needles again. I found that "voids" formed near the center of the needle and appeared to form between the grain boundaries at the area of bending. I suspected that the needle would show more failure at the surface of the bend where the needle was in tension, but instead the voids formed in the center of the needle, 2/3 of the way towards the side of the bend in compression. Why would this be? What is causing the needle to fail this way and in this area? 

    Thanks for any input!

    Sincerely,

    Adrian Brietzke 


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    Adrian Brietzke
    Celadon Systems
    Burnsville MN
    (507) 459-0594
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    ASM Handbook 23A


  • 2.  RE: Tungsten Rhenium Grain Boundaries

    Posted 5 days ago
    It looks from your description, that the cracks are where the transition between tension to compression happens.

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    Ytzhack Heber
    Metallurgist
    California Brazing
    Newark CA
    (510) 790-2300
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    ASM Handbook 23A