A fractographic study on tensile fracture surface of duplex microstructure TiAl alloy

摘要

The mechanical properties of TiAl altoys 4epend significantly on the microstructure. Introducing duplex mixrdstructure (DM) has improved ambient tensile plasticity and strength of TiAl alloys. Some aspects of the ductilizing mechanism have been established. The investigation of fracture behaviour on the side faces of compression test specimens indicated, that a2 phase does not inhibit the initiation of crack but rather can retard the propagation of a crack [1]. Observation of fracture surfaces demonstrated that ihe higher tensile ductility in DM is due to a small grain size and the fracture meriianisms are plasticity-induced grain boundary decohesion/and cleavage [2]. To reveal the fracture micromechanism and the function of Lamellar colonies in the process of deformation, detailed fractography and cleavage crystallography are needed.