Magnetic field and stress Induced strain in CoNiAl Ferromagnetic Shapememory Alloy

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• 作者：B. Rajini Kanth^a ; ^{rajani75@gmail.com} ; P.K. Mukhopadhyay^b
• 关键词：Ferromagnetic Shape Memory Alloys ; Beta Phase ; Gama Phase ; Martensitic Transformation ; Stress Induced Strain and Magnetic Field Induced Strain
• 刊名：Materials Today: Proceedings
• 出版年：2016
• 出版时间：2016
• 年：2016
• 卷：3
• 期：10
• 页码：3960-3965
• 全文大小：643 K
• 卷排序：3

文摘

Ferromagnetic shapememory alloys (FSMAs) are versatile and best materials for the application as sensors and actuators due to their smart behavior and faster response than the ordinary SMAs. Because of the ductility induced by the gamma phase precipitates and large range of martensitic and magnetic transformation temperatures CoNiAl FSMA is getting more importance and study of it is more interesting. We have made a CoNiAl alloy with the composition Co35Ni35Al30 by arc melting method. The sample was annealed at 1200°C/24h and quenched in water. It was characterized by XRD, SEM EDAX, DSC, and magnetization. From the XRD and SEM, the sample possesses two phases at room temperature (both β and γ). The Single phase (β) Co35Ni35Al30 alloy shows very sharp martensitic transition, but has extremely low ductility at room temperature. The presence of γ solid solution (disordered F.C.C. structure) as a second phase in the CoNiAl system renders the β-phase ductile at room temperature and makes it useful for practical applications. The transformation temperatures of the present CoNiAl alloy were obtained from DSC and four probe measurements. These were found to be TMs = 175 K, TMf = 153 K, TAs = 185 K and TAf = 205 K and Tc(β) = 225 K The magnetic field induced strain was measured at room temperature using NI 6210 data logger. M-H Curves at different temperatures (80 K, 150 K, 175 K, 200 K, 250 K, 300 K, 350 K and 400 K) were recorded using VSM. Stress induced strain at different stress levels was studied by Vibrating reed method (VBR). In the present paper we are presenting the magnetic field induced strain and stress induced strain near the martensitic transformation temperature of the sample. How the sample strain in the presence of magnetic field strength and stress level affect the behaviour of the sample in the vicinity of the martensitic transformation temperature.