The y(FCC)tt&(HC) transformation is studied by light optical microscopy and scanning electron microscopy in a polycrystalline Fe-Mn-Si-Cr-Ni shape memory alloy. Thermal and stress-induced martensites are both studied to point out differences. A color etching method permitted to clearly observe morphological evolutions during the transformation and its reversion. Deformations of a golden microgr...

We have investigated the effect of pressure and thermal ageing on transformation behavior of Ni-%45.16Ti shape memory alloy. 70-320 MPa pressure was applied and annealed at 500 o C for 2 hour to see the effect of applied pressure on transformation temperature. It was observed that the starting and final temperature of austenit increased, the martensite start temperature almost remain constant a...

In this paper we present a walking pattern filter for Shape Memory Alloy (SMA) actuated biped robots. SMAs are known for their slow response. The actuation speed limitation can potentially lead to stability problems for biped robots. This filter adapts the human motion for a SMA biped in order to have a stable walking pattern. The Zero Moment Point (ZMP) is used as a main criterion of the filte...

Shape Memory Alloys (SMAs) coatings of NiTi and NiTiHf have been deposited onto Si substrates using pulse DC sputtering. Coatings of NiTi with compositions containing 45 to 65 at% Ti have been fabricated by co-sputtering NiTi with Ti. NiTiHf coatings with Hf compositions ranging from 2 to 30 at% Hf have been fabricated by co-sputtering NiTi with Hf. XRD results reveal the as-deposited coatings ...

cryogenic treatment can be used as a supplemental treatment that is performed on some tool steels between quenching and tempering as an effective method for decreasing retained austenite and increasing wear resistance. in this research, the effect of deep cryogenic treatment (dct) on dimensional stability and mechanical properties of 80crmo12 5 tool steel was investigated. the martensitic trans...

We study plane strain thermomechanical deformations of a square block made of steel, and model a material defect in it by a rigid non-heat-conducting ellipsoidal inclusion located at the center of the block. The boundaries of the block are presumed to be thermally insulated, and its top and bottom surfaces compressed vertically at a prescribed rate. The loading pulse is assumed to be made up of...

The transformation texture was studied in a Ti–6Al–4V alloy for two microstructures produced through different phase transformation mechanisms (i.e. diffusional vs. displacive). Both microstructures revealed qualitatively similar crystallographic texture characteristics, having two main texture components with Euler angles of (90 , 90 , 0 ) and (90 , 30 , 0 ). However, the overall a texture str...