according  to my book (old), you should NOT count  on solder as  
mechanical  support of ANY kind.  solder is intended to  provide  
electrical connect, use solder, especially high temp  solder (assume  
you are going to use it at elevated temp for service, or assembly  
sequence - such as multiple reflows... it is difficult to count  on  
microstructure to be the same as you initially put down).
as for FEM purpose, I would use 50% book  value that tell you  - if  
i  were you...
my 1.5 cents.
jk
On Sep 20, 2018, at 9:54 AM, Stadem, Richard D wrote:

> Adding to what Dave said; you don't get something for nothing!  
> Different alloys have different physical characteristics and are  
> used for correspondingly different purposes and applications. Don't  
> attempt to use something not AABUS and fully documented on the  
> applicable BOM.
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of David Hillman
> Sent: Thursday, September 20, 2018 6:57 AM
> To: [log in to unmask]
> Subject: Re: [TN] High Temp SnPb solder
>
> Hi Ben - yes, there are differences in the mechanical properties  
> and the
> solder joint microstructures for the "high temp" alloys. Most of those
> alloys have applications in component construction, specifically in
> component die attachment. One very common alloy used frequently in  
> a number
> of applications is the 10Sn88Pb2Ag alloy.
>
> Dave Hillman
> Rockwell Collins
> [log in to unmask]
>
> On Thu, Sep 20, 2018 at 6:40 AM, Gumpert, Ben  
> <[log in to unmask]> wrote:
>
>> TechNetters,
>>
>> J-STD-006 has a series of 'high temp' SnPb alloys (some with Ag)  
>> that are
>> close in SOL/LIQ temps. I'm familiar with Sn10Pb90 as a common  
>> high-temp
>> ball on ceramic BGAs, but I haven't seen the others used. Are  
>> there any
>> differences (e.g. mechanical properties) among these that would drive
>> selection, other than the SOL/LIQ?
>> Are some alloys more readily available than others?
>>
>> Ben
>>