Effect of heat treatment on the grain size control, superplasticity, internal friction, and mechanical properties of zirconium-bearing aluminum-based alloy

Investigation of Effect of Preliminary Annealing on Superplasticity of Ultrafine-Grained Conductor Aluminum Alloys Al-0.5%Mg-Sc

“…The Al 3 Sc particles were coherent to the Al crystal lattice: the elastic strain fields were observed near the particles while the interphase boundaries between the Al 3 Sc particles and the Al crystal lattice were diffused ( Figure 5 e,f, see also [ 38 ]). No large elongated Al 3 Sc particles, the presence of which evidences the intermittent mechanism of the particle nucleation (see [ 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 ]) were found.…”

“…It was shown in [ 30 ] that intensive pore formation in the Al 3 Sc incoherent particles may be one of the factors limiting the ultimate superplastic characteristics of the UFG Al-0.5%Mg-Sc alloys. It should be stressed here that the formation of the Al 3 Sc particles in the investigated UFG alloys at reduced temperatures goes via a discontinuous precipitation mechanism (see [ 4 , 30 , 38 ]) similar to the low-temperature discontinuous solid solution decomposition in Al-Zr alloys [ 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 ].…”

“…The present papers were aimed at an additional verification of the hypothesis proposed in [ 30 ] on the effect of the Al 3 Sc particles on the superplastic characteristics of the UFG Al-0.5%Mg-Sc alloys. Note that the intermittent decomposition of solid solution leads to the formation of large dashed linewise Al 3 (REE,TM) incoherent particles at the grain boundaries in the Al alloys (see [ 30 , 39 , 40 ]). It may lead to an increased number of failures of the small-sized wires of 0.2–0.3 mm in diameter in the course of fabrication by drawing, rolling, or extraction.…”

A High-Strain-Rate Superplasticity of the Al-Mg-Si-Zr-Sc Alloy with Ni Addition

“…The heat treatment of as-cast material plays the most important role for the dispersoid strengthening and grain boundary pinning effect. The high density of fine L1 2 -strucutred Sc-and Zr-bearing dispersoids is observed after low temperature annealing [43,[62][63][64][65] and two-step annealing regimes [43,56,63,[65][66][67]. The homogenization annealing for the studied alloys was performed in two steps, with the first low-temperature step at 350 • C for 8 h and the second high-temperature step at 480 • C for 3 h to provide precipitation of the L1 2 dispersoids and fragmentation and spheroidization of the Al 3 Ni particles [29,52].…”

“…In novel alloys, the additions of Sc, as an expensive element, are reduced to 0.1 wt.%, while that of Zr is retained in a higher amount, 0.2 wt.% [ 32 , 49 , 50 ]. The bimodal distribution of the particles in the alloy’s structure provides a high strain rate superplasticity with strain rate sensitivity coefficient m above 0.3 for the AA5XXX- [ 24 , 30 , 51 ], AA7XXX- [ 29 , 30 , 42 , 52 ] and AA2XXX-types [ 27 , 34 ] alloys containing eutectic- and dispersoid-forming Fe [ 24 ], Ni [ 24 , 27 , 29 , 52 ], Ce [ 25 , 27 , 53 ], Y [ 34 ], Er [ 51 ], Mn [ 54 , 55 ], Cr [ 55 ], Zr [ 30 , 56 , 57 ], Sc [ 58 , 59 , 60 , 61 ]. The influence of the eutectic-forming and dispersoid-forming elements on the grain structure and superplastic deformation behavior of Al-Mg-Si type alloys is poorly studied.…”