Lamellar specimens of Cu-Zn-Al Shape Memory Alloy (SMA) were trained in bending under as much as 500 cycles, until two-way shape memory effect (2WE) was obtained. Trained specimens were further tested by means of a hydraulic installation where, heating-cooling cycles were performed in oil conditions. Considering that the lower concave surface of the specimens was kept in compressed state while the upper convex surface was kept in elongated state,

Samples of Fe-14Mn-6Si-9Cr-5Ni (mass. %) shape memory alloy were sintered from two powder mixtures: (i) as blended (0_MA) and (ii) equal amounts of as blended and mechanically alloyed (MA’d) powders (50_MA). In order to increase the compactness degree, different specimens were hot rolled at 1373 K and the last rolling pass was performed at four different temperatures: (i) room temperature (RT); (ii) 873 K; (iii) 1073 K and (iv) 1373 K. In order

The paper reports the evolution of surface relief and shape memory behavior in an Fe–28Mn– 6Si–5Cr (mass%) shape memory alloy (SMA) as a function of the applied hot working procedure. The objective of this paper is to discuss the relationship between surface relief characteristic, structural changes and the type of hot working processing. Particular aspects concerning the relief of martensite plates were reported after the alloy was subjected

Processing effects caused by homogenization heat treatment, hot rolling and solution treatment in three Fe-Cr-Ni-C alloys, with different Ni amounts, were analysed by optical and scanning electron microscopy. X-Ray diffraction (XRD), magnetic hysteresis data, Vickers micro-hardness and micro-indentation measurements were used in order to reveal chemical composition and processing effects. Dendrite fragmentation, caused by hot rolling and thermoelastic

Two different types of Fe-base shape memory alloys (SMAs), obtained by different processing methods, were comparatively analyzed from the point of view of: (i) structural characterization, (ii) morphologic aspects and (iii) mechanical behaviour. For this purpose, heat treated specimens of Fe-9Cr-4Ni-0.33C and in Fe-28Ni-17Co-11.5 Al-2.5 Ta (mass. %) were produced and prepared for X-ray diffraction (XRD) and scanning electron microscopy (SEM) observations,

An Fe-14Mn-6Si-9Cr-5Ni (mass. %) shape memory alloy obtained through powder metallurgy, containing a mixture of 50% commercial powders and 50% mechanical alloyed powders, was subjected to different heat treatments in order to increase chemical homogeneity degree. The heat treatments consisted of using three types of treatment atmospheres (air, nitrogen and argon) and three isothermal maintaining times (6 × 102 s, 24 × 102 s and 48 × 102 s). The

The paper reports the effects of 100 to 500 training cycles applied to lamellar specimens of a Cu-Zn-Al Shape Memory Alloy (SMA). The training procedure consisted in the bending, during the cooling to room temperature (RT) of martensitic specimens, by the load fastened at their free end and in load lifting by Shape Memory Effect (SME) during heating up to austenitic domain. During cooling, the concave surface of bent specimens was compressed and

Fe-14 Mn-6 Si-9 Cr-5 Ni (mass. %) shape memory alloys (SMAs) were produced from raw powders employed both in initial commercial state and in a mixture state of equal fractions of commercial and mechanically alloyed (MA’d) particles. After blending, pressing and sintering, powder compacts were hot rolled (HR’d) and solution treated (ST’d) before being machined into plane-parallel lamellas. Specimens with special geometry were pre-strained on

Lamellar thermal actuators, for temperature control in hydraulic systems, were manufactured from a Cu-Zn-Al shape memory alloy and trained in bending, between 100 and 500 cycles. The cycles were performed automatically and comprised electrical heating and ventilated air cooling during which a load, fastened at actuator’s free end, was lifted by shape memory effect and lowered by martensite-formation softening, respectively. The structural effects

The surface micro-reliefs of primary martensite plates, representative for two shape memory alloys (SMAs) with different crystalline structures were compared from qualitative and quantitative point of view by scanning electron microscopy and atomic force microscopy, respectively. Qualitative evaluations revealed larger widths and heights of the primary plates of e hexagonal close packed (hcp) martensite, in an Fe-Mn-Si-Cr-Ni SMA than those of b29