Effect of Pore Content on Mechanical Properties of Porous Nitinol under Compressive Loading

Porous NiTi shape memory alloys have shown good potentials for different functional to structural applications as well as biomedical applications. In the present study، highly porous shape memory NiTi alloy specimens were produced via space holder method using urea as a temporary material. The porous NiTi specimens exhibit good pore characteristics and interconnectivity that is appropriate for biomedical applications. Compressive mechanical tests were performed for NiTi specimens with porosity ranged from 42 to 70 percent. It is obvious that the mechanical properties such as Young’s modulu and strength of the porous NiTi decrease with increasing porosity. Apparent Young’s modulus of NiTi specimens decreases from 5. 3 to 3 GPa as porosity increases. Maximum recoverable strain of near to 8. 3% and 7 was achieved for porous NiTi specimens without urea and 50 vol. % urea، respectively. Furthermore، recoverable strain percent is almost constant for superelastic porous NiTi after several cycles.