Joining of UHTC Diborides using Metallic Interlayers

So-called Ultra-High Temperature Ceramics (UHTC) are the topic of reasonable and expanding worldwide research interest. The present work focused on ZrB2 and HfB2 which exhibit good thermo-mechanical and thermo-chemical properties, and good resistance to erosion and corrosion. A major obstacle to more widespread usage of UHTC diborides have been the adversity of processing. The fabrication of sizable complex-shape parts will be very challenging, and the practical use of these materials in complex structures will require effective methods of joining. Without joining methods, the full promise of these materials will not be realized. In the present work, transient liquid phase (TLP) bonding of HfB2-Xvol%MoSi2 (X=5 or 10) composites with a Ni/Nb/Ni interlayer was systematically performed at 1500 °C. It was revealed that well-bonded interfaces were achieved and the interfacial characteristics were highly depended on the content of MoSi2 as a sintering aid. In addition, joining of ZrB2-10vol%MoSi2 composite using Ti or Zr metallic interlayer was demonstrated at elevated temperatures. It was similarly found that well-bonded interfaces were produced. More results of microstructural analyses in detail and mechanical tests on the joints will be presented at the conference.