Isothermal decomposition of some β Cu–Zn–Al alloys with e/a=1.48

Kinetics of isothermal decomposition in polycrystalline β CuAlBe alloys

“…However, any later morphological evolution of the g 2 precipitates is not detected by this technique. It is remarkable that the same observation has been reported in the b / g 2 decomposition in Cu-Zn-Al alloys [9].…”

Optical microscopy of isothermally decomposed β copper based SM alloys

“…In general, isothermal treatments at moderate temperatures, between 473 and 773 K, in Cu‐based SM alloys with an electron atom ratio e/a near the eutectic one (1.50) produce β phase decomposition into the equilibrium γ and α phases (Castro & Romero, 1998, 1999a,b, 2000a,b).…”

“…1a). This treatment time is enough to produce γ and α precipitates (Castro & Romero, 1999a). Dark grey regions correspond to γ phase precipitates, whereas the white plates (light yellow) are α phase regions.…”

“…The parent β phase of the shape memory alloys (SMA), although stable at high temperatures is not often thermodynamically stable at lower temperatures. For example, the metastable β phase of CuZnAl alloys can undergo diffusional decomposition to the equilibrium phases, generally α and γ, during cooling (Pons & Portier, 1995, 1997; Lovey & Cesari, 1990) or by isothermal treatments at moderate temperatures, between 473 and 773 K (Castro & Romero, 1998, 1999a,b). This fact leads to a degradation of the shape memory capacity and a change in martensitic transformation temperatures (Auguet et al ., 1989; Lovey et al ., 1990; Garcia et al ., 1996).…”

Reducing the formation of FIB‐induced FCC layers on Cu‐Zn‐Al austenite

“…For example, Cu‐Zn‐Al SMAs with an electronic concentration near 1.48 show a transformation from a L2 1 ordered high temperature cubic austenite (β) phase to a low temperature monoclinic martensitic structure (Ahlers,1986). Different heat or irradiation treatments induce the precipitation of other phases that interfere with the martensitic transformation (Castro and Romero,1999; Zelaya et al,2007). Castro and Romero report on the formation of γ precipitates (D8 2 structure) for different aging treatments and for different sample compositions.…”