There is not. This has been a known limitation for some time.
In Aperture you should use the Version Name field for your picture titles.
I've been told that you can populate the Version Name field from the IPTC Title field using Applescript, but I don't know how to do it.
You can use the worthy plug-in BorderFX to put the contents of the Title field on top of or in the border of a picture. That is not, of course, the same as making the title part of the file name.
Feature requests to Apple for Aperture can be made via "Aperture➞Provide Aperture Feedback".