Superplasticity and thickness of liquid phase in the vicinity of solidus temperature in a 7475 aluminum alloy

Wetting of grain boundaries in Al by the solid Al3Mg2 phase

“…The direct HREM evidence for thin GB films and triple junction ''pockets'' has been recently obtained in metallic W-Ni [36,37] and Al-Zn [26] alloys. The observed splitting of the solidus line into conventional bulk solidus and novel GB solidus permitted explaining the mysterious phenomenon of the high strainrate superplasticity (HSRS) observed in several nanostructured Al ternary alloys and nanostructured Al metalmatrix composites, containing Mg and Zn [41][42][43][44][45][46][47]. The maximal elongation-to-failure increased drastically from 200-300% upto 2000-2500% in a very narrow temperature interval of about 10°C just below the respective solidus temperature.…”

Mechanical Behavior of AA6061 Aluminum in the Semisolid State Obtained by Partial Melting and Partial Solidification

“…[25][26][27][28] The authors related the formation of these thin filaments to a micro-superplasticity phenomenon involving high local deformation. This phenomenon has been linked to three possible deformation mechanisms: [25] viscous flow, single crystalline plasticity, or superplastic flow in microvolumes, but the first one was predominantly invoked to explain the formation of filaments, [26][27][28] i.e., the viscous flow of liquid or semiliquid grain boundary material. This explanation seems to be fully valid in the case of the deformation of alloys in semisolid state obtained both by partial solidification and melting.…”

Superplastic behavior of Al-coated Mg alloy sheet

“…Formation of the filaments is known as one of the micro-superplasticity phenomena [28]. This phenomenon was observed in a number of superplastically deformed materials [28][29][30][31][32][33][34][35][36][37][38][39][40][41].…”

“…The micro-superplasticity was suggested to correlate with several possible mechanisms: (1) viscous flow due to the existence of liquid-like or semi-liquid phase [29][30][31][32][33][34][35][36][37]; (2) single crystalline plasticity [38,39]; (3) severe elongation of cavities under the tensile stress [40]; (4) diffusion creep and the filament growth during the superplastic deformation [41]. However, the testing temperature, 573 K, for the present alloy was only about 0.62T m of pure Mg, much lower than the eutectic temperature of a Mg-Al binary alloy system, 710 K [39].…”