Intermetallic phase formation during combustion synthesis of mechanically activated Ni-Ti alloy

محورهای موضوعی : Mechanical Engineering

Seyed Khatiboleslam Sadrnezhaad ¹ , Shahin Katiraei ² , Abbas Ghasemi ³

1 - Sharif University of Technology
2 -
3 -

تاریخ دریافت : 1393/04/28 تاریخ پذیرش : 1396/08/09 تاریخ انتشار : 1393/09/10

کلید واژه:

چکیده مقاله :

Intermetallic phase formation and oxidation reaction during combustion synthesis (CS) of Ni-Ti equiatomic mixture are affected by mechanical activation (MA) and pre-heating conditions. Important parameters are ignition time, reaction duration, temperature rise, microstructural change, titanium oxidation and intermetallic phase formation. Superelasticity and shape memory effects are influenced by two-stage austenite-rhombohedral and rhombohedral-martensite transformations detected by differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) of the combusted samples. Tension tests indicated superelastic behavior after 1 h, production of Ni3Ti after ½ h and delayed superelastic/thermoelastic behavior after 2 h MA. Results indicate that pre-combustion heating fosters mono-phase formation and titanium oxidation; while mechanical activation lowers ignition-start-time, synthesis-duration and Ni3Ti formation.