Superplastic Behavior of Large Grained Iron Alluminides

Deformation mechanisms for superplastic behaviors in a dual-phase high specific strength steel with ultrafine grains

“…At the same strain rate (10 −3 /s), the normalized deformation temperature (T/ T m , where T m is the melting temperature) is plotted against the elongation to fracture in Fig. 3(b) for the HSSS, along with the data for the other steels and the intermetallic compounds [1,4,10,12,14]. As observed, the HSSS displays excellent superplastic properties when compared to the other steels and the intermetallic compounds.…”

“…Moreover, this value of Q for the HSSS is The normalized deformation temperature vs. the elongation to fracture for the HSSS, along with the data for the other steels and the intermetallic compounds [1,4,10,12,14]. In (a), the strain rate sensitivities (SRS, m) are also given for the experiments conducted at 973 K. much lower than the creep activation energy of 370 kJ/mol reported for binary Fe-28Al [32] and 450 kJ/mol reported for binary Fe-40Al [33].…”

“…High elongation to fracture, i.e., superplasticity is possible to be achieved under certain conditions [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. It is now well established that two fundamental conditions should be satisfied in order to achieve superplastic deformation in metals and alloys: 1) High homologous temperature (generally with a testing homologous temperature of T/ T m > 0.5, where T m is the absolute melting temperature) is needed; 2) A relative small grain size is required since grain boundary sliding (GBS) is an important deformation mechanism during superplastic flow and GB density increases with decreasing grain size.…”

Fine‐structure superplasticity in materials

“…Polycrystalline structures containing low-angle grain boundaries can be made superplastic by converting the low-angle boundaries to high-angle boundaries by appropriate thermal or thermomechanical treatment [169]. It is noted that, sometimes, superplasticity can still take place in a structure containing low-angle grain boundaries [89,106]. For example, in some alloys that 661 continuously recrystallize during deformation, lowenergy boundaries evolve into high-angle boundaries in the early stage of deformation, prior to significant cavitation.…”

“…Fe 3 Al and FeAl [87,89]. For example, a Fe 3 Al alloy (Fe-28Al-2Ti) showed superplasticity at strain rates from 2x10~4 to 4x10~3 in temperatures ranging from 700 to 900°C.…”