The Study on Microstructures and Properties of the Direct Squeeze Casting Al-Zn-Mg-Cu-Zr-Sc Alloy

Abstract

Trace elements Sc was added to the Al-Zn-Mg-Cu-Zr alloys, the differences of the microstructure and properties using gravity casting and squeeze casting are compared. The result shows that through the addition of trace elements Sc, the Al-Zn-Mg-Cu-Zr alloys casting microstructure was refined effectively, dendrite segregation was alleviated and the mechanical property of alloy was enhanced. Using squeeze casting forming could improve the compactness of the alloys, decrease the probability of occurrence of shrinkage cavities, porosity and segregation, in addition, the grain could be refined by the pressure forced on the alloy melt. Combined the element Sc microalloying and squeeze casting used in Al-Zn-Mg-Cu-Zr alloy forming, we could get the casting with uniform, compact, little defect microstructures. This combination could provide a new way to the Al-Zn-Mg-Cu-Zr alloy forming.

Semi-Solid Precision Forming Process of High-Strength and Wear-Resistant Aluminum Matrix Composites

“…Comparing the dendrite size of in 7050 area, when the specific pressure is lower, it can be clearly seen that the secondary dendrite arms are coarser and the secondary dendrite arm spacing is larger. In pressure solidification, the higher the specific pressure in a certain range, the faster the solidification, and the growth of secondary dendrites can be effectively restrained [8].…”

Research on Characteristics of Heat Treatment of Squeeze Cast Al-Cu-Mg Alloy

“…5e). According to the research of Wang et al [17], fine and dispersive metastable precipitates (GP zone and θ′′ phase) were formed in squeeze casing Al-5Cu alloy during natural aging, while rod-like stable precipitates (θ phase) formed during artificial aging. So, the T4-treated squeeze cast alloy exhibits greater elongation and nearly the same tensile strength compared to that by T6 heat treatment, as shown in Fig.…”

Research on Microstructure and Mechanical Properties of Rheological Die Forging Parts of Al-6.54Zn-2.40Cu-2.35Mg-0.10Zr(-Sc) Alloy

“…This reduces the network structure formed by the development of dendrites, and avoids the formation of a coarse eutectic phase during the solidification process [31], which reduce the micro-segregation between grains. Research [20] shows that in the process of melt cooling, the crucible wall with a lower temperature provides undercooling According to Figure 12, the intergranular T phase structure is uniformly distributed, and no Sc and Zr-containing phases are observed in and between the grains. We used graphic processing software to make statistics on the content of the intergranular phase, which in 1#, 3# and 6# is 7.71%, 7.24% and 6.38%, respectively.…”

“…This reduces the network structure formed by the development of dendrites, and avoids the formation of a coarse eutectic phase during the solidification process [31], which reduce the micro-segregation between grains. Research [20] shows that in the process of melt cooling, the crucible wall with a lower temperature provides undercooling for the nucleation of Al 3 (Sc, Zr) particles, and electromagnetic stirring makes the temperature field composition field more uniform, which can increase Al 3 (Sc, Zr) particle stability. Research [32] shows that IC-AEMS has both the advantages of rapid cooling and uniform temperature field and composition field, and the role of the inter-cooling rod is similar to the crucible wall, which can provide the melt with more undercooling required for Al 3 Zr nucleation, and IC-AEMS can inhibit the growth rate of Al 3 Zr particles.…”