If I deliver a change set to a stream and not associate it with a work item can the change set be associated with a work item after it has been delivered ?
Yes.
The changeset itself is closed upon delivery to the stream.
But its associated work-item(s) is not: you can add or remove one or several work-items in association with the delivered changeset.
That being said, I have a special hook which makes that association mandatory on deliver: ie, you cannot deliver without having first associated your change set first to a Work Item.
I am not sure if that hook is a custom one for my organization, but here is where you can check if it is there:
It is in the Project Area administration, under
Team Configuration /
Operation Behavior /
Source Control /
Deliver (client) /
Preconditions and follow-up actions are configured for this operation /
Require Work Items and comments
来源：https://stackoverflow.com/questions/13360232/can-i-associate-a-change-set-with-a-work-item-after-it-has-been-delivered