Two-Step Martensitic Transformation in an Aged Ti50Ni15Pd25Cu10 High Temperature Shape Memory Alloys
S.U. Rehmana, M. Khan a, A. Nusair Khan b, L. Ali a and S.H. Imran Jaffery a
aSchool of Mechanical and Manufacturing Engineering (SMME), National University of Science and Technology (NUST), Islamabad, Pakistan
bInstitute of Industrial Control System (IICS), Rawalpindi, Pakistan
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Multi-step martensitic transformation in an aged Ni-rich binary NiTi shape memory alloy is considered as usual behavior during transformation from austenite to martensite phase; From (austenite) B2 to R-phase and then R-phase to B19' (monoclinic). However, for equi-atomic NiTi-based quaternary high temperature shape memory alloy, two-step martensitic transformation was detected for the first time. The Ti50Ni15Pd25Cu10 high temperature shape memory alloys were investigated for the evolution of transformation temperatures at aging temperature of 550°C and 700°C. Aging at 550°C for 6 h resulted in significant reduction of phase transformation temperatures. During forward transformation from austenite to martensite, two-step martensitic transformation B2 → R and R → B19 (orthorhombic) was observed. By aging the alloy at 700°C for 6 h, no significant effect was found on phase transition behavior and transformation temperatures.

DOI: 10.12693/APhysPolA.128.B-125
PACS numbers: 81.30.Kf