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Subject:
From:
"Grossmann, Guenter" <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Grossmann, Guenter
Date:
Tue, 27 Apr 2010 15:12:20 +0200
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Ioan
Yep, looks like fatigue. No wonder, you have a lead with a stiff geometry and I assume it's Alloy42 on an epoxy board. Solder joint- thickness below the component was around 20um. A solder joint- killer. The size of the phases is not particularly big in my opinion.

Best regards

Guenter

>-----Ursprüngliche Nachricht-----
>Von: TechNet [mailto:[log in to unmask]] Im Auftrag von Ioan Tempea
>Gesendet: Dienstag, 27. April 2010 15:00
>An: [log in to unmask]
>Betreff: [TN] Failure fatigue photos
>
>Dear Technos,
>
>
>
>It looks like, for the first time, I have the occasion to look at
>fatigue failed joints. The lab analysis we've got states this, but does
>not abounds in details.
>
>
>
>One of the conclusions is "the crack propagates around harder Sn
>shearing the softer Pb, but the Sn and Pb zones seem fairly large for
>regular solder structure". Citing from Klein Wassink "During cyclic
>plastic deformation the microstructure inside the material changes in
>the zones where the deformation is concentrated. This leads to local
>grain growth..."
>
>
>
>I have deposited the micro-sections on the IPCs website http://ipc-
>technet.groupsite.com/gallery/13116
>
>
>
>I would need your expert opinion regarding the failure. Is this fatigue?
>The big pure Sn and pure Pb areas, are they normal size for fatigued
>joints?
>
>
>
>Thanks,
>
>
>
>Ioan Tempea, ing.
>Ingénieur Principal de Fabrication / Senior Manufacturing Engineer
>T | 450.967.7100 ext.244
>E | [log in to unmask] <mailto:[log in to unmask]>
>W | www.digico.cc <http://www.digico.cc/>
>
>
> N'imprimer que si nécessaire - Print only if you must
>
>
>
>
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