A novel Ti/TiAl laminated composite with excellent shear properties

In this study, Ti/TiAl laminated composites consisting of Ti layer, α₂-Ti₃Al interfacial reactive layer, and TiAl layer were successfully prepared by spark plasma sintering using alternately stacking Ti and TiAl powders. The corresponding microstructural evolution and shear strength of the laminated composites were systematically studied. Laminated composites with different intermediate layers (Ti layer, TiAl layer, and Ti₃Al layer) showed different shear fracture behaviors, and the ultimate shear strength of Ti layer, TiAl layer, and Ti₃Al layer reached about 622 MPa, 466 MPa, and 328 MPa, respectively, indicating excellent shear performance. Different interlayer shear tests showed different crack extension behaviors, the main cracks in Ti₃Al intermediate layer propagated along stress direction and penetrated into Ti₃Al layers. The crack growth in TiAl intermediate layers revealed that the main cracks initiated from TiAl layer and extended to the Ti₃Al layer with weak shear strength. When the ductile Ti layer was sheared, the Ti intermediate layer can release the applied shear stress by the plastic deformation and the residual shear force transferred to the Ti₃Al layer forming microcracks. The excellent shear properties of novel Ti/TiAl laminated composite was attributed to the in-situ reaction transition interface.