Let's state the Android parts and wifi seem to not care where you are. However there are cellular carriers that will not give access to some phones. This is THEIR CHOICE on the matter and not dictated by you or Samsung.
As to if there is any technical issue you would have to determine which cellular capability this model has and then see if the cellular carrier you plan to use has support for that. Rarely no one but you will do that research.
I am planning on buying the galaxy grand from Kuala Lampur, Malaysia. I have heard that this phone is unlocked so it will work out of Malaysia as well. I plan on using this phone in Brazil, where I live. Will it work?
Thanks in advance!