Multistage homogenization process of aluminum alloy 2618

Abstract

Single‐, two‐, and three‐stage homogenization treatments of heat‐resistant alloy 2618 were conducted in this study. Results reveal a low melting point Al2CuMg phase and high melting point Al2Cu phase in the as‐cast aluminum alloy 2618. After single‐stage homogenization at 495 °C for 10 h, the Al2CuMg phase dissolves completely, but the Al2Cu phase cannot be completely dissolved even once the homogenization time is prolonged to 18 h. After the alloy 2618 are homogenized using two stages: 495 °C for 10 h and 520 °C for 8 h, a portion of the Al2Cu phase remains in the alloy. The Al2Cu phase remains undissolved even after prolonged time. After the two‐stage homogenization treatment at 495 °C for 10 h and 540 °C for 5 h, the high melting point Al2Cu phase completely dissolves but overburn occurs. After the alloy 2618 are homogenized using three stages at 495 °C for 10 h, 520 °C for 5 h, and 540 °C for 3 h, the Al2Cu phase completely dissolves and no overburn is detected. The three‐stage homogenization treatment is an effective method for dissolving the high melting point Al2Cu phase in the alloy 2618 and increasing their overburn temperature and solid solution temperature.

The Effect of Melting-Casting and Heat Treatment Process on the Hardness of 2618 Aluminum Alloy

“…The results show that with the increase of the melting-casting temperature in the range of 740 ℃~900 ℃, the hardness of the alloy increases rapidly firstly, then decreases slightly, and finally increases slightly, and the hardness of the alloy is the most uniform at 900 ℃. The main reason is that the liquidus temperatures of Al-10%Fe and Al-10%Ni alloys are 880 ℃ and 600 ℃ respectively, while the liquidus temperature of Al-50%Cu alloy is lower than 600 ℃ [3,4] . Therefore, the structure inheritance caused by Al-10%Ni and Al-50%Cu is eliminated when the melt is kept at 740 ℃ for only 10 min.…”