Hello Rich,
Look for Solder Properties Database at:http://www.metallurgy.nist.gov/solder/
which is one good starting point. Most upcoming conferences in the field have
presentations on material properties as well (APEX, TMS in March etc...).
Also check out the lead-free or property links at: http://www.npl.co.uk/ei/

Now, IMHO*, not much has been validated for a wide range of circumstances or
for solder in solder joints of real assemblies. So, available properties
(which are all excellent in and of themselves) have to be reviewed within the
context of each experiment ( stress / strain rate / temperature range, specimen
geometry, load type, process, heat-treatment etc...).

There is development activities going on because things are not as settled as
they have been portrayed in casual discussions.  For example,  comparisons of
SAC** and SnPb creep data show that, under high enough stress, SAC creeps as
fast, sometimes faster than SnPb regardless of temperature in the range -55C
to 125C.  This can be encountered in accelerated testing but also in use with
rapid transients or large temperature swings, with quite a few reliability
implications.  This goes against the conventional and short descriptions of SAC
properties that you 'll find here and there, but that 's what the hard data
shows when you look at properties over a wide range of conditions.  The
fundamentals behind it are not understood yet. There was some discussion to that effect
on this forum (last Summer I believe).  I have since gathered much more
supporting evidence and will present some of that in lead-free events at the
upcoming APEX conference.

Jean-Paul

* IMHO = In My Humble Opinion
** SAC = SnAgCu

In a message dated 2/12/2004 2:02:01 PM Eastern Standard Time,
[log in to unmask] writes:
Can anyone recommend a site where I can get the technical details of the
SAC alloys that are being considered for Lead-Free?

A concise table showing the mechanical properties is really what  I'm
looking for.

_____________________________________
Jean-Paul Clech
EPSI Inc.
Home page URL: http://jpclech.com
P.O. Box 1522
Montclair, NJ 07042
USA
tel: 973-746-3796
fax: 973-655-0815

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