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shape-memory-behavior
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Synthesis of FeNiCoTi powder alloy by mechanical alloying and investigation of magnetic and shape memory properties
, Article Journal of Superconductivity and Novel Magnetism ; Volume 25, Issue 6 , March , 2012 , Pages 1893-1899 ; 15571939 (ISSN) ; Madaah Hosseini, H. R ; Sharif University of Technology
Springer
2012
Abstract
FeNiCo base powder alloy with nominal composition Fe-27Ni-17Co-4Ti (wt%) was prepared from elemental powders by mechanical alloying. The structure of milled powders was characterized by XRD and SEM. The effect of nanosize structure on magnetic properties and shape memory behavior was studied using VSM and DSC. After milling for 240 minutes by high energy vibrational ball mill under argon atmosphere, supersaturated solid solution formed with mean crystallite size of ∼20 nm. Results of VSM examinations showed that by milling for 240 minutes saturation magnetization and intrinsic coercivity reached 304 emu/gr and 21 Oe, respectively. XRD analyses made it clear that transformation from BCC to...
Characterization of constrained aged niti strips for using in artificial muscle actuators
, Article International Journal of Engineering, Transactions A: Basics ; Volume 24, Issue 4 , 2011 , Pages 321-329 ; 17281431 (ISSN) ; Sadrnezhaad, S. K ; Sharif University of Technology
Abstract
Marvelous bending/straightening effects of two-way shape memory alloy (TWSMA) help their employment in design and manufacturing of new medical appliances. Constrained ageing with bending load scheme can induce two-way shape memory effect (TWSME). Scanning electron microscopic (SEM) analysis, electrical resistivity measurement (ERM) and differential scanning calorimetry (DSC) are employed to determine the property change due to flat strip constrained aging. Results show that flat-annealing prior to the aging shifts NiTi transformations temperatures to higher values. Superelastic behavior of the as-received/flat- annealed/aged samples with more adequate transition temperatures due to...
Improved adhesion of NiTi wire to silicone matrix for smart composite medical applications
, Article Materials and Design ; Volume 30, Issue 9 , 2009 , Pages 3667-3672 ; 02641275 (ISSN) ; Hassanzadeh Nemati, N ; Bagheri, R ; Sharif University of Technology
2009
Abstract
Recent uses of intelligent composites in biomedical appliances aggrandize the necessity of bonding-strength improvement in NiTi/silicone matrix interface. SEM micrographs and pull-out tests are employed to determine the strength of the NiTi/silicone bonds in a flexible composite piece. Greater adhesion strengths are obtained due to the presence of thin oxide layer, surface roughness and frictional forces between the embedded-wires and the contacting phase. Effect of curing treatment on phase transformation temperatures of the wires is determined by electrical resistivity (ER) measurements. Results show that the curing treatment shifts the transition points of the wires towards higher...