[PDF] Top 20 Effect of Internal Strain on Martensitic Transformations in NiTi Shape Memory Alloys

... (5) The changes in chemical composition are caused by the precipitation process. Thus, they have the diffusion character and do not lead to the occurrence of well- separated regions of different compositions in the sample. ... See full document

... superelastic NiTi strip specimens with nano-grain size. The NiTi superelastic strip specimen’s Apparent Young’s Modulus (AYM) and the critical stress decrease when the specimen is subjected to an external ... See full document

... these alloys were prepared by arc melting using pellets of Ni (3N), flakes of Mn (3N) and pellets of Ga (4N) as starting ...these alloys were grown by a floating zone method with a growth rate of ... See full document

... new shape, which it will ...actuation. Shape memory alloys, however, are not for all ...common shape memory material is an alloy of nickel and titanium called ...Ni-Ti ... See full document

... TiNi alloys can dramatically decrease the martensite transformation temperature and R phase transformation and martensite transformation are accordingly ...TiNiFe alloys exhibit two-step martensitic ... See full document

... applied strain at surface was 1.5­1.6%. After unloading, shape recovery was measured by heating using a cigarette ...a strain increment of 1% was also carried out for 2Nb at RT using an Instron-type ... See full document

... The quality of EDM surfaces is assessed by surface integrity. The significant parameters of the surface include; surface topography, surface roughness, surface cracks, hardness distribution and metallurgical changes in ... See full document

... of martensitic plates by excess dislocations retained on quenching from high temperature [11] ...The shape memory effect is a temperature-dependent ...During shape memory ... See full document

... extraordinary shape memory and superelastic properties [8, ...thermoelastic martensitic transformation under thermal or mechanical loading conditions at different ...initial shape. This is the ... See full document

... the alloys cold worked before heat treatment exhibit the fracture stress around 1000 MPa, while the fracture strain at the M phase state drops below 20% by cold working before heat ...the strain of ... See full document

... the shape memory alloys are mainly due to the martensitic transformation occuring in the material when mechanical or thermal load- ings are ...the effect of strain rate on the ... See full document

... the effect of external fields on martensitic transformations is very important to understand the essential problems of the transformation, such as thermodynamics, ki- netics and the origin of the ... See full document

... the shape memory and the superelastic forms of NiTi are ...the shape and the properties of the item ...the shape memory effect exhibited by NiTi shape ... See full document

... 1.6) alloys is investigated. The addition of Gd results in a change in the microstructure. With the increase of Gd content, the grain size is clearly reduced and the volume fraction of the second phase increases ... See full document

... of shape memory alloys and especially of Ni– Ti are considered to be one of the most promising solution for the development of new microactuators required for many applications in the field of micro ... See full document

... Magnetization measurements were performed using a Bitter-type water-cooled pulsed magnet (inner bore: 26 mm; total length: 200 mm) in Akita University. The magnetic field was applied along the longitudinal axis of the ... See full document

... A NiTi shape memory alloy, known as nitinol, has been intensively studied for last five ...The NiTi alloy with large size is commonly produced by vacuum sintering, thermal explosion mode of ... See full document

... having a Ni/Ti atomic ratio of 1.100 and with Nb contents of 6 and 9 at%. A total of five alloys were fabricated. The alloy compositions were analyzed using inductively coupled plasma atomic emission spectroscopy ... See full document

... Figure 9 shows stress-strain curves of 16Nb4.9Sn at 298 K, which are drawn from records in a tensile testing machine, as a function of time in air cooling (0, 10, 20 and 40 s), where loading and unloading are ... See full document

... Ti-45 to 50 at%Pd alloys were prepared by arc melting in an argon atmosphere. The starting materials were pure Ti (99.7 mass%) and pure Pd (99.8 mass%). Ingots of 20 g in weight were melted repeatedly six times ... See full document