Effect of Trivalent Additions and Processing on Structural and Magnetic Transitions in Ni-Mn-Ga Ferromagnetic Shape Memory Alloys

  • R. P. Mathur Defence Metallurgical Research Laboratory, Hyderabad
  • R. K. Singh Defence Metallurgical Research Laboratory, Hyderabad
  • S. Ray Indian Institute of Technology Roorkee, Roorkee
  • P. Ghosal Defence Metallurgical Research Laboratory, Hyderabad
  • V. Chandrasekaran Defence Metallurgical Research Laboratory, Hyderabad
Keywords: Ferromagnetic shape memory alloys, Ni-Mn-Ga alloys, martensitic transformation

Abstract

Ferromagnetic shape memory Ni50Mn30Ga15Al5-xBx (x = 0, 1, and 4) alloys were prepared by vacuum arc melting and subsequent heat-treatment as well as by melt spinning to investigate the effect of trivalent element additions in ternary Ni-Mn-Ga alloys. The heat-treated alloys containing Al were reported to possess a modulated martensite structure, however alloy containing both Al and B showed a loss of modulated structure in martensite formed. The rapidly solidified alloys on the other hand showed the formation of a similar modulated structure without composition change in alloys containing Al and the alloys containing Al and B. In addition, the former showed a presence of an amorphous phase with latter showing crystalline boron rich phases. The magnetisation of the B containing alloys in both the processing technique was however very low, showing lower magnetic exchange interaction in such alloys.

Defence Science Journal, 2012, 62(4), pp.252-260, DOI:http://dx.doi.org/10.14429/dsj.62.1279

Author Biographies

R. P. Mathur, Defence Metallurgical Research Laboratory, Hyderabad

Dr R.P. Mathur obtained BE from Rajasthan University, Jaipur, and MTech from Indian Institute of Technology, Kanpur, in 1982and 1991, respectively. He has obtained hisPhD from Indian Institute of Technology, Roorkee, in 2008. Presently, he is working as a Scientist at Defence Metallurgical Research Laboratory (DMRL), Hyderabad. His areas of research interest include: amorphous alloys, nano structured soft/hard magnetic materials,rare earth permanent magnets, functional materials such as shape memory alloys. He has published about 25 research papersin reputed international journals and more than 30 papers innational/international conference proceedings.

R. K. Singh, Defence Metallurgical Research Laboratory, Hyderabad
Mr R.K. Singh obtained his BTech(Metallurgical Engineering) from the Indian Institute of Technology, Roorkee and MTech (Metallurgy) from Institute of Technology, Banaras Hindu University, Varanasi, in 2002 and 2006, respectively. Presently, he is working as a Scientistat DMRL, Hyderabad. His research area includes: development of ferromagnetic shape memory alloys, Ni-Ti based shape memory alloys, Sm-Co-based permanent magnets and other magnetic materials for defence applications.
S. Ray, Indian Institute of Technology Roorkee, Roorkee
Prof (Dr) Subrata Ray obtained his MTech and PhD from IIT, Kanpur. Presently, heis working as Professor, Metallurgical and Materials Engineeringin University of Roorkee. He has research interests inmaterials development with special emphasison cast metal matrix composites (MMC). He has many pioneering contribution in cast MMC including introduction of stircasting and addition of surface active elements for which he held the first patent. He has also developed interest onmaterials used in Li-ion batteries. He has published more than 200 technical papers, mostly in international journals and hand books including those of ASM and ASLE. He is afellow of the National Academy of Sciences, India, and Indian National Academy of Engineering.
P. Ghosal, Defence Metallurgical Research Laboratory, Hyderabad
Dr Partha Ghosal obtained PhD in Metallurgical Engineering from IT, Banaras Hindu University in 1996. Presently, heis working as a Scientist in the Electron Micoscopy Group at DMRL. He is recipient of Young Microscopists Award (2001) from EMSI and DRDO–Laboratory Scientist of the Year Award (2006). His research interests are nanomaterials cha-racterisation and defects characterisation using electron microscopy and has more than 15 years of experience. He has published 35 research papers in reputed international journals and more than 45 papersin national/international conference proceedings/presentations. He has delivered 25 invited lectures and is the author of 2 patents. He is a life member of IIM, EMSI, MSI and MRSI.
V. Chandrasekaran, Defence Metallurgical Research Laboratory, Hyderabad
Dr V. Chandrasekaran obtained his PhD from Annamali University, Tamil Nadu. He is Ex-senior scientist of DMRL. His areas of research interest include: Rareearth permanent mag-nets, magnetostrictive, magnetocaloric, ferromagnetic shape memoryand nanostructured soft/hard materials. He has published more than 40 papers in international journals. He was a recipient of MRSI medal (1990), Vasvik Industrial Research Award (1991) and Metallurgist of the Year Award (1998).
Published
2012-07-03
How to Cite
MathurR., SinghR., RayS., GhosalP., & ChandrasekaranV. (2012). Effect of Trivalent Additions and Processing on Structural and Magnetic Transitions in Ni-Mn-Ga Ferromagnetic Shape Memory Alloys. Defence Science Journal, 62(4), 252-260. https://doi.org/10.14429/dsj.62.1279
Section
Materials Science & Metallurgy