EDM surface characteristics and shape recovery ability of Ti35.5Ni48.5Zr16 and Ni60Al24.5Fe15.5 ternary shape memory alloys

An experimental study of influence of wire electro discharge machining parameters on surface integrity of TiNiCo shape memory alloy

“…7(b). Similar trend have been observed by Hsieh et al 21 during the machining of TiNi based ternary alloys.…”

“…Longer pulse duration generally leads to higher discharge energy per unit cycle that melts more material and re-solidifies them as well due to rapid quenching by constantly flowing de-ionized water on the machined surface. 21 During our observation thicker recast layer was found at high pulse on time (125 ls) and lower servo voltage (20 V) while it was thin comparatively at lower pulse on time (105 ls) and higher servo voltage (60 V) which can be seen in Fig. 6.…”

“…Converted layer is not much affected during WEDM process hence hardness was almost constant in this zone. Such kind of variation in hardness were noticed by Hsieh et al 21,23 during the electro discharge machining of TiNiZr and TiAlfe alloys.…”

Influence of Zirconium Percentage on Microhardness and Corrosion Resistance of Ti50 Ni50-xZrx Shape Memory Alloys

“…The patterns in Figure 1 show that all the alloys present the characteristic phases of the shape memory effect; the austenite phase FCC (B2) was found on planes (100),(101),(200) and the monoclinic martensite phase (B19'), on planes (111), (210), (111); similar identification was found by Hsieh & Wu 12 and Evirgen et al 9 . Characteristic peaks of titanium oxides TiO 2 (211) and TiO(202) were formed, and so were zirconium oxides (311), because these elements are highly reactive to oxygen, as also found by Hsieh et al 18 . While Ti atoms migrate to form TiO 2 and TiO particles, residual Ni atoms diffuse into the TiNi matrix to form Ni-rich regions, and then the Ni 4 Ti 3 (223) and Ni 10 Zr 7 (422) phases appear 18,19 .…”

“…Characteristic peaks of titanium oxides TiO 2 (211) and TiO(202) were formed, and so were zirconium oxides (311), because these elements are highly reactive to oxygen, as also found by Hsieh et al 18 . While Ti atoms migrate to form TiO 2 and TiO particles, residual Ni atoms diffuse into the TiNi matrix to form Ni-rich regions, and then the Ni 4 Ti 3 (223) and Ni 10 Zr 7 (422) phases appear 18,19 . Also in the N5 and N10 alloys, other phases appear, e.g., λ1 and NiZr phases and the coexistence of the austenite and martensite phases, which was also found by other authors 19,20 .…”