**4. Conclusions**

In this study, a reliable brazing joint of medical titanium and alumina bioceramic was successfully obtained using Au foil. The microstructure, reaction products, and shear strength of titanium/Au/Al2O3 joints were studied. The conclusions are summarized as follows:


**Author Contributions:** Conceptualization, X.S. and W.L.; Formal analysis, H.B.; Investigation, H.B. and S.D.; Project administration, J.F.; Resources, Y.L.; Supervision, X.S.; Validation, S.H.; Visualization, Y.J.; Writing—original draft and revising, H.B.; Writing—review and editing, all the authors; Writing—revising, S.H. and W.L.

**Funding:** This project is supported by the National Natural Science Foundation of China (Grant Nos. 51775138, U1537206 and U1737205), and the Key Research & Development program of Shandong Province (No. 2017GGX40103).

**Conflicts of Interest:** The authors declare no conflict of interest.
