A multivariant martensitic Cu-Zn-Al-Fe Shape Memory Alloy has been analysed by means of tensile loading-unloading tests, X-ray diffraction and scanning electron microscopy. The tensile superelastic curve was correlated with the crystallographic reorientation of the martensite plate variants. The stress plateaus correspond to the reversible formation of (016) variant, up to 20 MPa, accompanied by the increase of the second and third order microstrains

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

In the framework of intelligent materials, actuators, sensors and control systems have been developed in an attempt to replicate the main functions performed by muscles, nerves and brain, respectively [1]. The actuators have been developed from various types of intelligent materials such as: piezoelectric, shape memory; electro and magnetostrictive and electro and magnetorheological materials that have the general ability to react to thermal, electric,

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

The calorimetric response of a martensitic Cu-Zn-Al-Fe shape memory alloy (SMA) was evaluated during second heating, up to 453 K, with different rates ranging between 1.67 × 1022 and 1.67 × 1021 K s21, performed on a differential scanning calorimeter (DSC). Heating rate (HR) variation caused a marked change of the endothermic peak aspect, which was observed on the DSC thermograms recorded during second heating and associated with the martensite

In this work, Fe-Mn-Si based powder mixture having shape memory alloy composition prepared by mechanical alloying and systematically studied under different milling conditions. Effect of ball to powder ratio (BPR), type and amount of binder addition were investigated as process parameters. All mechanical alloying studies were performed under argon atmosphere and stainless steel balls and vials were used as milling media. X-Ray diffraction (XRD),

A normalized hot forged Cu-15Zn-6Al (mass. %) shape memory alloy (SMA) was subjected to tempering heat treatments meant to enhance the reversion to parent phase (austenite) of thermally induced martensite. By means of differential scanning calorimetry (DSC) the reversibility of martensitic transformation was verified during constant-rate heating-cooling cycles. The results have showed that 373 K- tempering destabilized martensite and enabled its

In order to produce shape memory rings for constrained-recovery pipe couplings, from Fe-14 Mn-6 Si-9 Cr-5 Ni (mass%) powders, the main technological steps were (i) mechanical alloying, (ii) sintering, (iii) hot rolling, (iv) hot-shape setting, and (v) thermomechanical training. The article generally describes, within its experimental-procedure section, the last four technological steps of this process the primary purpose of which has been to accurately

The reproducibility of thermally induced reversible martensitic transformation, occurring in a Cu-15Zn-6Al (mass-%) shape memory alloy during heating, was studied on three different fragments of martensitic alloy subjected to complex thermal cycling comprising four series of five heating-cooling cycles, applied on a differential scanning calorimetry (DSC) device, between room temperature (RT) and three maximum temperatures: 453, 463 and 473 K respectively.