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 > > > > >______________________________________________________________________ >This email has been scanned by the MessageLabs Email Security System. >For more information please contact helpdesk at x2960 or >[log in to unmask] >______________________________________________________________________ > >--------------------------------------------------- >Technet Mail List provided as a service by IPC using LISTSERV 15.0 >To unsubscribe, send a message to [log in to unmask] with following text >in >the BODY (NOT the subject field): SIGNOFF Technet >To temporarily halt or (re-start) delivery of Technet send e-mail to >[log in to unmask]: SET Technet NOMAIL or (MAIL) >To receive ONE mailing per day of all the posts: send e-mail to >[log in to unmask]: SET Technet Digest >Search the archives of previous posts at: >http://listserv.ipc.org/archives >Please visit IPC web site >http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional >information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 >ext.2815 >----------------------------------------------------- ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________ --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------