Superelastic behavior and stabilization of stress-induced martensite in Cu-13.4Al-4.0Ni single crystals

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ÂÛÎÄ×÷Õߣº³ÂÇ츣 ÕÔÁ¬³Ç R. Stalmans J. van Humbeeck

ÎÄÕÂÒ³Â룺161 - 165

Key words£ºSuperelasticity£» Stabilization£» Stressª²induced martensite; CuAlNi single crystal; Destabilization

Abstract: By applying tensile stress along ¡´100¡µ of ¦Â phase, the superelastic behavior and stabilization of stress-induced martensite (SIM) of Cu-13.4Al-4.0Ni(mass fraction, %) single crystals were studied. The results show that the pseudo-yield stress decreases with the increase of cycling number, and keeping load isothermally has an effect on stabilization of SIM. Previous thermal cycling between (M_s-20 ¡æ) and (A_f+20¡æ) promotes the superelasticity and the stabilization of SIM as well; the pre-thermal cycling also reduces the pseudo-yield stress. However, once the stabilization of SIM is produced, it can be destabilized by either the afterwards thermal cooling-heating cycling or load and immediately unload cycling in (A_f¡«M_d ). Isothermal treatment in (A_f¡«M_d ) brings restabilization of SIM. The maximum superelastic value from ¦Â¡ú¦Â₁¡ä(18 R ) is 9% for the studied single crystal. When test temperature is in A_f¡«(A_f+50¡æ) and stress is in 0¡«350 MPa, the superelastic behavior exist.