Is it permissible for a man to allow his wife to travel abroad for study after she has been accepted for a scholarship?

A woman is not permitted to travel except with a mahram. If a mahram is available, and there is safety from temptation and intermingling, and she observes the limits set by Allah, then her husband may allow her to study abroad. Otherwise, it is not permissible. It is better for a woman to remain in her home.