Effect of microstructure on the tensile property of porous Ti produced by powder metallurgy technique

摘要

Porous Ti with the porosity of 50% and the average pore size of 200 μm was prepared by powder metallurgy technique using polymethyl methacrylate (PMMA) as space holder. The microstructure, tensile deformation and final fracture behavior were investigated. Porous Ti reveals two kinds of pores: open interpenetrated macro-pores in the range of 30-260 μm and micro-pores with the average size of 9 ± 2 μm. The stepped surface of macro-pores consists of polygons with angles of 30°, 60° or 90°. The ultimate tensile strength of porous Ti is 81 MPa. Porous Ti fails with the formation of shear bands at 45° to the tensile axis. The cracking of the struts on porous Ti is controlled primarily by the macro-pores. Fractography shows evidence of the brittle cleavage fracture in porous Ti. The failure mechanism has been discussed by taking the intrinsic microstructural features into consideration.