Is this possible?
There’s two settings for this.
Under Settings / Basic - “Open external links in a new tab. Users can change this in their preferences.”
I assume this setting is for non-registered users? Setting this ON in admin does NOT change anything for registered users.
You need to go into your own profile preferences and check off " Open all external links in a new tab".
Is there a way we can default this setting to checked/on for new users?
Done. I had it set like that for myself, but forgot that for most people clicking links takes them out of the forum, which then might make it hard to navigate back. Opening links in a new tab keeps the forum open so it’s easier get back into the experience. Thanks for bringing that up and reminding me 
i just checked again and somehow when I am logged out the link won’t open in a new tab, but if I am logged in the link opens in a new tab but somehow not links to the aragon forum.
Yeah I dunno, but you should be able to configure it for yourself however works best for you. I’d focus on that
