The Treasure Fleet got as far as East Africa.
When (iotl) the Chinese government changed leaders and governing philosophies, the Treasure Fleet program was abruptly closed down and anything related to it was stomped out.
It is conceivable that with continued administration support, the Treasure Fleet would have gone around the Cape of Good Hope and made its way up the west coast of Africa.
Given its mission involved the known world, no, it is not.
There is no reason for it to do so. It was not searching for new territory or new conquests, so what's the point of sailing in hopes of finding something?
Edit: I was going with the flap-of-butterfly-wings-causing-typhoon perspective, so, my theory from that POV isn't a huge stretch, I think.
This isn't a Chinese equivalent to Columbus or Magellan. And getting that would take a very significant POD - not mere chance.