Both the superelastic and the shape memory properties of the cubic NiTi alloy known as Nitinol arise from two-phase transitions; from a simple cubic austenite phase to a trigonal R-phase and to a lower symmetry martensite phase. In this article, we speculate that two competing forces drive these transitions. One is “mechanical” in nature and it takes the cubic austenite structure of NiTi to a d...

In this study, patterned microindents are generated on the surface of NiTi shape memory alloy by laser shock assisted direct imprinting (LSADI). During LSADI, the plasma pressure generated by the laser pulse punches the mask into the target material and thus generates patterned indents. It has been demonstrated that thermally controllable surface pattern can be generated on NiTi surface through...

The largest amount of latent heat the martensitic transformation in nickel titanium shape memory alloy was explored. measured amounts alloys with different compositions between 48.0 at.% Ni and 51.0 were compared. \(-\) 37.8 J/g absorption 34.8 emission obtained as averaged values several samples equiatomic composition. These magnitudes are close to those novel storage ceramics, VO2 (51 J/g) Ti...

We conducted the measurement of the hardness-depth relationship of NiTi shape memory alloy with a sharp Berkovich indenter. Different from most ductile metals, NiTi reacts to the mechanical load of indentation through phase transition underneath the indentation tip. We found that the hardness decreases rapidly with the increase of the indentation depth and eventually approaches a constant. To u...

In this study, an umbrella-shaped device that is used for osteonecrosis treatment is simulated. The femoral head is subjected to various complex loadings as a result of a person's daily movements. Implant devices used in the body are made of shape memory alloy materials because of their remarkable resistance to wear and corrosion, good biocompatibility, and variable mechanical properties. Since...

It is well known that the Fe based alloys can exhibit shape memory effect due to the y to E martensitic transformation. The effect may not be as striking as observed in the NiTi alloy but it might become attractive fkom the practical point of view. In this work, two compositions of Fe-Cr-Ni-Mn-Si(-Co) stainless steel based shape memory alloy, prepared by the VIM technique, will be presented. Th...