Hi Alex,

I am unaware of any data that exists on fatigue behavior of LIGA Ni.
I am working on a project that uses LIGA nickel and would be very
interested in obtaining a copy of any information you receive.

Initial work I was directing resulted in the inability to initiate a
fatigue crack in LIGA Ni.    A modified C(T) type specimen was being
used.

Using a single edged notched bend specimen, at  reasonable K (stress
intensity levels) fatigue crack initiation and growth could not be
achieved without plastic deformation of the specimen.  These
observations led to the preliminary conclusion that elastic fatigue
crack propagation will not be a failure mode for LIGA Ni; whereas,
cross section fatigue (or plastic deformation upon cyclic loading) is
the predominant fatigue mechanism.

If you are interested I can put you in touch with the researchers
that performed this work.

In addition,  Kevin Hemker and Bill Sharpe, Jr. from Johns Hopkins
University are beginning to investigate cyclic response of LIGA
nickel and other MEMS materials as a part of on-going research.  I am
working with them by providing specimens and technical direction to
study material microstructure - property relationships in LIGA
Nickel.

If you have any questions, please feel free to contact me.  Also,
please provide me with copies of other responses to your question.

Good Luck!

Howard Last

> Date:          Thu, 05 Aug 1999 14:27:01 -0500
> From:          Alex Freeman 
> Reply-to:      [email protected]
> Subject:       LIGA Ni fatigue cycles
> To:            [email protected]

> Hi Researchers,
>
> Does any one have data regarding the LIGA Ni spring fatigue behavior?
> What life times can one expect below the yield stress? Thanks,
>
> alex
>
> --
> Alex Freeman, Ph.D
> Research Scientist
> Zyvex
> 1321 N. Plano Rd, #200
> Richardson, TX 75081
> 972-235-7881 x219
>
>
Howard Last
[email protected]
Ph: (301) 744 - 1927
FAX: (301) 744 - 6698
Naval Surface Warfare Center
Code 420, Bldg: 301
101 Strauss Ave
Indian Head, MD 20640-5035