Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Aluminium alloy will change strength

  1. Apr 12, 2005 #1
    Is it the case that an Aluminium alloy will change strength (yield/ultimate) if subjectet to a varying load instead of a static one? I can't quite see why it should...can someone help me with this?
     
  2. jcsd
  3. Apr 12, 2005 #2

    FredGarvin

    User Avatar
    Science Advisor

    You need to phrase your question a bit better. Are you talking about cyclic loads past the elastic limit? Are you referring to an S-N curve issue? Or are you possible talking about work hardening?
     
  4. Apr 12, 2005 #3

    Gokul43201

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    I suspect it is the former.

    (TSN, you could look up "fatigue" and its origin in the "Bauschinger Effect". )
     
  5. Apr 12, 2005 #4

    Gokul43201

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    On the other hand, several Al-alloys are strengthened by work hardening...
     
  6. Apr 13, 2005 #5
    Well, I have two questions to answer. First, which Al alloy is the strongest, and in what region would the yield/ultimate strengths for this alloy lie?
    Second, Is this region the same if the alloy is subjectet to cyclic loads instead of static loads?

    On the first question I suspect the combination AlCu4Mg2 is the strongest, but I'm not at all sure...
     
  7. Apr 13, 2005 #6

    FredGarvin

    User Avatar
    Science Advisor

    There are so many different alloys of aluminum out there, this is a bit of a tough question to answer.

    Of the basic alloys that I am familiar with, 7001-T6 has the highest tensile strength of approximately 97 ksi. 7001-T6 is a zinc-copper-magnesium alloy that is age hardened.

    In terms of cyclic loading, this is where you will want to look up an S-N curve for that material. The endurance limit for this alloy is 21.8 ksi which, as shown is for 500x10^6 cycles (infinite life). To answer your question, it will depend on how much load you are cyclically placing on the material. If you are continuously cycling past the yield point, you will strain hardent the material. In that case it will become stronger, but also much more brittle and, obviously, the fatigue life drops.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Aluminium alloy will change strength
  1. Aluminium alloys. (Replies: 6)

Loading...