Intermetallic TiAl was induction brazed to steel in an induction furnace with Ag-Cu-Ti filler metal at 1143 K for 0?2-2?4 ks. Microstructural analysis indicates that Ti, Al, and C atoms in base metal diffuse to the interface and react strongly with the filler metal during brazing. The interface structure of the joint can be divided into three distinct zones: the reaction layer near TiAl, composed of Cu-Al-Ti compounds and Ag based solid solutions; the central zone of the interface, consisting of Ag based solid solutions in which Ag-Cu eutectic phases are dispersed; a TiC reaction layer adjacent to the steel. The relationship between brazing parameters and tensile strength of the joints is discussed, and the optimum induction brazing parameters obtained. When brazed at 1143 K for 0?9 ks, the tensile strength of the joint is 298 MPa.

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Dynamic softening behaviors of a promising biomedical Ti-13Nb-13Zr alloy under hot deformation conditions across dual phase α + β and single phase β regions were quantitatively characterized by establishing corresponding dynamic recovery (DRV) and dynamic recrystallization (DRX) kinetic models. A series of wide range hot compression tests on a Gleeble-3500 thermo-mechanical physical simulator were implemented under the strain rate range of 0.01-10 s −1 and the temperature range of 923-1173 K. The apparent differences of flow stress curves obtained in dual phase α + β and single phase β regions were analyzed in term of different dependence of flow stress to temperature and strain rate and different microstructural evolutions. Two typical softening mechanisms about DRV and DRX were identified through the variations of a series of stress-strain curves acquired from these compression tests. DRX is the dominant softeni ng mechanism in dual phase α + β range, while DRV is the main softening mechanism in single phase β range. The DRV kinetic model for single phase β region and the DRX kinetic model for dual phase α + β region were established respectively. In addition, the microstructures of the compressed specimens were observed validating the softening mechanisms accordingly.