Influence of Annealing Temperature on the Properties of Co-Ni-Ga Ferromagnetic Shape Memory Alloy

• DOI: 10.4028/www.scientific.net/amr.52.63
• Publication Date: 2009-03-16T10:45:05Z
• Authors: Sidananda Sarma; A. Srinivasan
• Keywords: Ingot; Tetragonal crystal system; Liquid nitrogen

Polycrystalline ingot of Co47Ni23Ga30 alloy was prepared by arc melting constituent elemental powders under argon atmosphere. The then vacuum sealed in a fused silica ampoule, homogenized at 1230 °C for 24 hours and quenched liquid nitrogen. X-Ray diffraction patterns the as-quenched samples revealed single-phase tetragonal structure. separately annealed 900 °C, 1000 1150 6 subsequently ice water. alloys exhibited singlephase martensite structure (β′-phase) room temperature, whereas, presence face centred cubic (γ) phase along with observed pieces 0C, respectively. martensite-austenite structural change this using Differential Scanning Calorimeter. It found that austenitemartensite transition temperatures (As, Af, Ms Mf) shifted to higher when annealing temperature increased. Curie towards lower as percentage γ-phase increased alloy. saturation magnetization did not show any appreciable changed. Presence additional γ- below confirmed Optical Microscopy Electron analysis. influence on properties ferromagnetic shape memory composition is discussed paper.