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Scientists discover galling

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  • Scientists discover galling

    http://www.sciencedaily.com/releases...0911151945.htm

    Doesn't take much to impress them

  • #2
    The behavior was captured in movies that show the flow in color-coded layers just below the surface of the copper specimen. Copper is commonly used to model the mechanical behavior of metals.
    Perhaps we should send them a note mentioning that "by the way, copper doesn't really act like most other metals..."

    High thermal conductance, extreme and nearly instant work hardening from very soft to very hard, huge variation of ductility and the fact that copper and its many compounds have a range of anomalous magnetic and mechanical properties at the same mesoscale being studied.
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    • #3
      I think if you apply enough pressure the bonds between grains are going to give. These bonds are variable in strength, so the give is not going to be completely linear. It is no surprise to me that on that small of a scale there's going to be variations in how the grains move around. Now give me the research money please.
      I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

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      • #4
        Next they are going to patent the forming tap.
        Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.

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        • #5
          Maybe they'll stumble across friction welding if they carry on like this.
          Richard - SW London, UK, EU.

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          • #6
            They need to talk to some experienced bench machinsts. My view of a gall is it starts with a nucleation particle penetrating the oil film, followed by friction plating from relative motion, followed by momentary or intermittant adhesion producing a scratch that propagates laterally something like a boat wake. I've seen it in soft metals, hard metals, glass, waxes, large scale (glacier) small scale (watch screws) etc.

            Galling is not a specific mechanism limited to an isolated class of materials. It's a general phenomenom widely found whereever closely fitted parts are subject to loaded localized bearing.

            It's odd that galling is being investigated anew even though (dubious) anti-galling remedies have been around since the Egyptians. Soot and animal grease for example. Still works.
            Last edited by Forrest Addy; 09-13-2012, 06:48 AM.

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            • #7
              This sounds like a materials science issue, so I am kind of surprised it was on the cover of PRL, a respectable journal (not magazine) that is usually for physicists.

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              • #8
                What a breakthrough!
                Andy

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                • #9
                  Forrest, Forrest, Forrest! Shame on you! To be so ARROGANT as to think that a PURE REASEARCH SCIENTIST would even CONSIDER asking a dirty-handed real-world metal worker his/her ideas on ANYTHING! WELL, I am shocked I tell you, SHOCKED!
                  Duffy, Gatineau, Quebec

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                  • #10
                    Originally posted by beanbag View Post
                    This sounds like a materials science issue, so I am kind of surprised it was on the cover of PRL, a respectable journal (not magazine) that is usually for physicists.
                    That's the same read I get -- they're observing the effects of galling at the micron level.

                    Too bad you knuckleheads didn't publish your micrographs of fluid-flow at the point of contact, and noted the material folding was responsible for galling. You might have gotten a paper out of it

                    "Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did."

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                    • #11
                      You see a lot of this when you run the end mill backwards.

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                      • #12
                        The NHS in the UK had a rather interesting problem with hip joints, Galling perhaps?
                        mark
                        http://www.dailymail.co.uk/health/ar...her-types.html

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                        • #13
                          [QUOTE=boslab;795838]The NHS in the UK had a rather interesting problem with hip joints, Galling perhaps?
                          mark
                          /QUOTE]

                          Or corrosion caused by two metal contact.

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                          • #14
                            That's funny! Sounds like they've discovered cutting as well. "The folding and cracking were most pronounced when the steel piece was held at a sharp angle to the copper surface".

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                            • #15
                              Come on now. As scientists, they are interested in uncovering the first principles origins of Things That Everybody Already Knows. I can also assure you that many young and upcoming scientists are unaware of the concept of galling.

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