“…Similarly, the Cr to Ni substitution changed the FCC to a BCC structure [20]. Interestingly, an increase in the Al fraction resulted in structural changes from BCC to FCC (Al–Cu–Cr–Fe ∼ Al 2 –Cu–Cr–Fe) [21]. Figure 1 XRD patterns of ball-milled powders.…”
In this study, nanoporous high-entropy alloys (HEAs) were fabricated by chemically de-alloying aluminium atoms in mechanically alloyed HEAs. In addition, the effect of alloy composition, compositional uniformity, and porosity of the HEA precursors on the pore structures of the final HEA foams was investigated. Aluminium was successfully de-alloyed only for Ni-free HEAs because of the low mixing enthalpy of Ni and Al. For HEAs containing pre-existing microscale pores, aluminium atoms were readily de-alloyed because the pores opened pathways for NaOH, thereby resulting in hierarchical micro-nanoporous structures in the final foams. For denser HEAs with better compositional uniformity, homogeneous nanoporous structures were revealed in the final foams.
“…Similarly, the Cr to Ni substitution changed the FCC to a BCC structure [20]. Interestingly, an increase in the Al fraction resulted in structural changes from BCC to FCC (Al–Cu–Cr–Fe ∼ Al 2 –Cu–Cr–Fe) [21]. Figure 1 XRD patterns of ball-milled powders.…”
In this study, nanoporous high-entropy alloys (HEAs) were fabricated by chemically de-alloying aluminium atoms in mechanically alloyed HEAs. In addition, the effect of alloy composition, compositional uniformity, and porosity of the HEA precursors on the pore structures of the final HEA foams was investigated. Aluminium was successfully de-alloyed only for Ni-free HEAs because of the low mixing enthalpy of Ni and Al. For HEAs containing pre-existing microscale pores, aluminium atoms were readily de-alloyed because the pores opened pathways for NaOH, thereby resulting in hierarchical micro-nanoporous structures in the final foams. For denser HEAs with better compositional uniformity, homogeneous nanoporous structures were revealed in the final foams.
“…Presumably, these reactions comprise dissolution of metastable GP-zones that had formed in the supersaturated DC-cast state [28]. The first exothermic peak in the range 250 … 300 °C – also not present in AA 3103 – is ascribed to the formation and subsequent dissolution of metastable β’-(Mg,Si) phases [15,28,46]. At temperatures exceeding 350 °C, the solute Si begins to precipitate with Mg by forming Mg 2 Si particles [15,16,19].…”
Section: Discussionmentioning
confidence: 99%
“…. 300 °C -also not present in AA 3103 -is ascribed to the formation and subsequent dissolution of metastable β'-(Mg,Si) phases [15,28,46]. At temperatures exceeding 350 °C, the solute Si begins to precipitate with Mg by forming Mg 2 Si particles [15,16,19].…”
Section: Evolution Of Dispersoids In Mg-containing Alloys Aa 3005 And...mentioning
An important aspect of the characterisation of non-heat-treatable Al alloys is the constitution of the material in terms of its alloying elements in solid solution and, in turn, volume, size, morphology and species of second-phase particles. These constitutional characteristics, conveniently summarised as micro-chemistry, have an impact on physical and mechanical materials properties of Al semi-finished products. In the present study, the evolution of micro-chemistry in the Al–Mn alloys of the AA 3xxx series during solidification and homogenisation is analysed. Especially, we focus on the impact of additional alloy elements, including Si, Mg and Cu, on the phase selection during solidification and the changes in solute level and volume, size and type of second-phase particles during subsequent homogenisation.
“…According to the DSC analysis results and the references [7,8], the ranges of homogenization process parameters were determined as follows: homogenization temperature 400~600°C, holding time 6~18 hours. The specific process parameters were setting up as follows: (1) homogenization temperature: 400°C, 450°C, 500°C, 550°C, 600°C; (2) holding time: 6h, 9h, 12h, 15h, 18h.…”
Influence of homogenization on mechanical properties of Al-1Mn-1Mg alloy prepared by different melttreatments was discussed and mechanism of metallurgical defects on ingots' mechanical properties was analyzed. It was found that metallurgical defects, such as the inclusions and gas holes, cannot be removed from the original ingots by homogenization; the average increasement of tensile strength of the ingots prepared by comprehensive melt-treatment and homogenized at 400~500°C for 12 hours was 17.4%, and the elongation improved slightly; the better obdurability of the ingots can be obtained due to the vast reduction of crack initiation of metallurgical defects such as the inclusions, gas holes and so on; the fracture mode gave priority to the type of transcrystalline and micropore gathering; under the experiment condition, the relatively optimized processing permanents of homogenization can be obtained by heating at 450~500°C while holding for 12 hours and air cooling; the comprehensive mechanical properties of the ingots, prepared by the optimized process, can be tested as follows: b 180~193MPa, 16.0~18.0%..
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