Effect of secondary aging on microstructure and properties of cast Al-Cu-Mg alloy

Abstract

Al-Cu-Mg alloys have been widely used as structural materials for the aerospace industry due to their high tensile strength, toughness and good processability [1][2][3][4][5] . The hardness and strength of Al-Cu-Mg alloys are low, and pitting corrosion, intergranular corrosion (IGC) and local corrosion always occur in Al-Cu-Mg alloys [6,7] , which limit their industrial applications. Therefore, improving the comprehensive properties of Al-Cu-Mg alloys has always been the focus of research.Numerous studies have shown that heat treatment can significantly enhance the properties of Al-Cu-Mg alloys [8][9][10] . The standard T6 process can improve the mechanical properties of Al-Cu-Mg alloys, but the improvement is limited. To further improve the mechanical properties of the alloy, Lumley et al. [11] proposed the secondary aging process. The secondary aging process means that the standard T6 process is interrupted for a period at a lower temperature. The secondary aging process is called the T6I4 or T6I6

Study on Microstructures and Properties of the Al. Alloy Vacuum Die-Cast Parts of TL117 and C611

“…These fine suspended particles create the best condition for the nucleation of liquid Al. alloy and are conducive for the parts to form fine equiaxed grains [12].…”

“…Moreover, under the effect of the modifiers, the grains are closer to spherical shape. In the process of tensile deformation, the α-Al phase grains that grow up with Al3Zr particle as the core, will hinder some slip surfaces to move, thus form a large number of dislocations and improve the tensile strength of parts [12]. As for elongation of C611, the precipitation of Si and other enhanced elements is not sufficient, the matrix has certain lattice distortion, which will lead to increasing of the matrix hardeness.The plasticity and toughness will be reduced.…”

Effect of Electro-Pulse on Microstructure of Al-Cu-Mn-Zr-V Alloy during Aging Treatment and Mechanism Analysis

“…Al-Cu alloy is one of the representative high-strength cast aluminum alloys, which has excellent mechanical properties and has been widely used in the fields of aerospace, defense, and civil tools [1,2]. The addition of alloying elements such as Mn, Zr, V, and Ti can significantly improve the thermal stability, high-temperature performance, and corrosion resistance of Al-Cu alloys [3][4][5].…”