TiB and La2O3 reinforced titanium matrix composite is in situ synthesized by common casting and hot working technologies. Steady state creep behaviors of the matrix alloy and the TiB plus La2O3 reinforced composite are investigated in the temperature range 873-973 K. Creep resistance of the composite is significantly enhanced by the reinforcements. Steady state creep behaviors of the matrix alloy and composite are both controlled by dislocation climbing. The refined TiB whiskers La2O3 particles are responsible for the threshold stresses. Creep enhancement of the composite can be mainly attributed to threshold stresses at lower temperatures and stress transfer effects at higher temperatures. A power-lawconstitutive equation for steady state creep of the composite is built up.

(TiB+TiC)/Ti-6Al-4Vcomposite and Ti-6Al-4V alloywere hydrogenated. The phaseswere identified byXray diffraction (XRD). Microstructures of hydrogenated titanium matrix composite (TMC) and Ti-6Al-4V alloywere examined by optical microscopy (OM). Dependence of transformation temperatures on hydrogen concentration was determined by metallography. The transformation temperatures decrease with hydrogen and reach a minimum at hydrogen concentrations of 0.40 wt.% and greater. High temperature tensile tests were performed. The results indicate the elongation is improved at low and high hydrogen concentration but little at medium hydrogen concentration. The stress decreases at low hydrogen concentration, reaches a minimum at medium hydrogen concentration and then increases at high hydrogen concentration. Proper hydrogen concentration favors high temperature deformation of TMC.

This work investigates the cold workability of TiNbTaZr biomedical titanium alloys. During cold rolling, the alloy exhibits excellent workability. Dislocations slipping, stress-induced martensite phase transformation and deformation twins appear during the deformation. With the increase of the reduction of cold deformation, dislocations slipping contributes much to the plastic deformation. The mechanical properties with higher strength, better elongation and lower elastic modulus are obtained at the reduction of 99%. Grains refinement is also obtained during the deformation of dislocations slipping.

Titanium matrix composites reinforced with TiB, TiC and Y2O3 are fabricated by a non-consumable arc-melting technology utilizing chemical reaction between titanium, B2O3, B4C and Y. Microstructure of in situ synthesized Y2O3 was observed by scanning electron microscope (SEM), transmission electron microscope (TEM) and high-resolution transmission electron microscope (HREM). The Y2O3 forms in a way of nucleation and growth. Primary Y2O3 tends to grow in dendritic shape and becomes coarse. Secondary Y2O3 mostly grows in sphericity and the size is very small. Moreover, there is no fault in the Y2O3 reinforcements. The interface between Y2O3 and titanium was observed by means of TEM and HREM. Three groups of crystallographic relationships between Y2O3 and Ti were found. The interface between the Y2O3 and the titanium matrix is very clean and well bonded, and there is no interfacial reaction.