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Effect of annealing on stress‐induced transformation behaviors at low temperatures in a Ti–51.8 at.% Ni shape memory alloy
Author(s) -
Niitsu Kodai,
Kainuma Ryosuke
Publication year - 2014
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.201350418
Subject(s) - materials science , annealing (glass) , transmission electron microscopy , pseudoelasticity , crystallite , microstructure , shape memory alloy , alloy , composite material , metallurgy , martensite , nanotechnology
For polycrystalline Ti‐51.8Ni (at.%) specimens annealed at 473 and 943 K, the microstructures at room temperature were observed by transmission electron microscopy and the stress‐induced transformation behaviors at low temperatures were investigated by compressive test. The precipitation of Ti 3 Ni 4 was confirmed in the both annealed specimens, where the precipitates at 943 K had a lenticular shape in micrometer size, and those at 473 K seemed to be clusters in nanometer size. Superelasticity with almost complete shape recovery was detected at temperatures below 200 K for all the annealed specimens. In comparison to the as‐homogenized specimen, although the temperature dependence on the stress hysteresis only slightly changed in each annealing condition, the equilibrium stresses in the specimen annealed at 473 and 943 K apparently increased and decreased, respectively.