Scott

Yes, in my opinion there is a difference whether you go for thermal cycling
(air / air) or for thermal shock (liquid / liquid).
The deformation of soft solder takes place with two different deformation
mechanisms. Grain Boundary Sliding ( activated with slow deformation/high
temperatures) and Dislocation Climb ( activated with fast deformation / low
temperatures) .
Each deformation mechanism has its own damaging characteristic. Therefore
it does matter which deformation regime is activated during the test. In
reality Dislocation climb does not occur. This is the reason, why I think
that thermal shock tests are not a very sensible thing for reliability
testing of solder joints.

Best regards

Guenter

##############################################################
TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c
##############################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body:
To subscribe:   SUBSCRIBE TECHNET <your full name>
To unsubscribe:   SIGNOFF TECHNET
##############################################################
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information.
For the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311
##############################################################