====== Default SSH user ======

A better solution than putting an alias in your bashrc, would be to use a ssh config file
<code bash>
cat ~/.ssh/config

HOST *  
USER root
</code>
You can also specify certain subdomains use certain users. Useful if your laptop travels between networks.
<code bash>
HOST 192.168.*.*
USER homeuser

HOST 10.2.*.*
USER workuser
</code>
You could even configure by domains, and use different ssh keys for different domains.
<code bash>
HOST *.microsoft.com
USER bill
IdentityFile ~/.ssh/microsoft/id_rsa

HOST *.apple.com
USER steve
IdentityFile ~/.ssh/apple/id_rsa
</code>

====== More resources to read: ======
  * https://www.ssh.com/ssh/config/
  * https://www.cyberciti.biz/faq/create-ssh-config-file-on-linux-unix/