The effect of amount of deformation on the martensitic transformation and shape memory effect in a Fe-16Mn-5Si-9Cr-4Ni alloy is studied. It is found that both 6and a'martensite are induced by deformation. With increasing amount of deformation, y+~-nx' transformation is greatly enhanced. the highest shape memory strain 3 3% is reached when the amount of deformation is about 5%.

Shape Memory Alloys (SMAs) undergo stress and temperature induced reversible diffusionless crystalline phase transformations between a high synmaetry phase (austenite) stable at high tenlperatures and low stresses, and a low symmetry phase (martensite) stable at low temperatures and high stresses. Unusual macroscopic effects arise from these crystallographic changes, chiefly shape memory and su...

A process for fabrication of shape memory alloy MEMS actuators on a elastomeric polymer substrate is described. These actuators are designed for use on innovative soft body robots. Patterned shape memory alloy (nitinol) is sputter deposited on a polyimide mesh structure. The mesh substrate acts as a bias spring to de-twin the shape memory alloy in the martensite phase. Significant portions of t...

Shape memory polyurethanes (SMPUs) are thermally activated shape memory materials, which can be used as actuators or sensors in applications including aerospace, aeronautics, automobiles or the biomedical industry. The accurate characterization of the memory effect of these materials is therefore mandatory for the technology's success. The shape memory characterization is normally accomplished ...

High temperature shape memory polymers that can withstand the harsh temperatures for durable applications are synthesized, and the aromatic polyimide chains with flexible linkages within the backbone act as reversible phase. High molecular weight (Mn) is demanded to form physical crosslinks as fixed phase of thermoplastic shape memory polyimide, and the relationship between Mn and glass transit...

Magnetically sensitive shape memory poly(styrene-b-butadiene-b-styrene) copolymer (SBS)/liner low density polyethylene (LLDPE) composites filled with various contents of Fe3O4 nanoparticles were prepared. The influence of the Fe3O4 nanoparticles content on the thermal properties, mechanical properties, fracture morphology, magnetic behavior, and shape memory effect of SBS/LLDPE/Fe3O4 composites...

Amorphous polymers exhibit a rich landscape of time-dependent behavior including viscoelasticity, structural relaxation, and viscoplasticity. These time-dependent mechanisms can be exploited to achieve shape-memory behavior, which allows the material to store a programmed deformed shape indefinitely and to recover entirely the undeformed shape in response to specific environmental stimulus. The...

In shape-memory polymers, changes in shape are mostly induced by heating, and exceeding a specific switching temperature, T(switch). If polymers cannot be warmed up by heat transfer using a hot liquid or gaseous medium, noncontact triggering will be required. In this article, the magnetically induced shape-memory effect of composites from magnetic nanoparticles and thermoplastic shape-memory po...