Cyclic torsional loading of pseudoelastic NiTi shape memory alloys: Damping and fatigue failure

摘要: Abstract This paper investigates the mechanical response of pseudoelastic NiTi shape memory alloys to cyclic torsional loading. Emphasis is placed on effects cycling stress shear hysteresis. The area hysteresis decreases with increasing cycle numbers and this reflects what referred as “functional fatigue”. It also shown that classical structural fatigue occurs. Experiments were performed for cylindrical specimens (hollow solid shafts) using partly fully reversed at frequencies ranging from 0.1 1.0 Hz. Cyclic ruptures observed in between 3201 19,188 cycles. characteristic features rupture studied scanning electron microscopy; cracks always started processing defects near surface. Fatigue striations detected surfaces. results represent first analysis loading alloys. reports corresponding data provides a microstructural interpretation failure. contribute better understanding functional damping applications.