Search this site for transfer viva, there's been a fair bit of chat about this lately. Your questions will mainly be specific to your research to assess your understanding of your topic and, in particular, the data you are presenting. However, you should be prepared to talk about how you will develop your research to fulfill the requirements for a PhD i.e. how will you/have you expand(ed) upon current knowledge and what is (what will be) novel about your research. Good luck!