PowerShell Array output format [duplicate]

In Power Shell I try to get all members of an AD group with the following command:

$users=Get-ADGroupMember -Identity 'AD-Group-XYZ' -Recursive | Select SamAccountName

Then if I try to print the first username by typing:

$users[0]

I get the following output:

SamAccountName
--------------
usenameX

The question is how can I get only the output:

usenameX

and skip:

SamAccountName
--------------

I tried the following but nothing works:

$users[0].ToString()
$users[0].text
$users[0].text.ToString()

The reason is that I want to iterate in all usernames and create a string where I concatenate them and split them with a space.