How do I access the external materials web portal? Yes I have a premium subscription
You may find this article useful as well: http://www.javelin-tech.com/blog/2015/10/solidworks-user-defined-materials/
For the record, it is enough to have Simulation Professional subscription: http://help.solidworks.com/2017/English/SolidWorks/cworks/t_applying_Material_SW_Web_Portal.htm?id=4583806827d54efc91a92a64b76324b7#Pg0&ProductType=&ProductName=
IMHO it is best never to use SW material properties as there are many errors in them. Find a reliable source(s) and build your own library. If you are working w/ others you can save that library to the network and have everyone point to that file.
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