|研究了“双8时效”制度和“短时效”制度对Inconel 718高温合金母材和焊缝区的金相组织、室温力学性能的影响。结果表明，焊缝区为铸造组织特征，定向生长的树枝晶内析出γ″ 和γ′ 强化相，枝晶主干细长挺直，两侧的二次枝晶以δ相为主，形态短而直。由于“短时效”热处理的温度偏高，使γ″ 亚稳定相向δ稳定相转变，导致“短时效”热处理后焊件的显微硬度和强度略低于“双8时效”热处理试件，而断后伸长率基本无变化。
|关键词: 高温合金 电子束焊 时效热处理 微观组织 力学性能
|The effects of heat treatments on the microstructure and properties of Inconel 718 electron beam welding joints
Zheng Xin, Shi Yuying, Chen Yubao， Zhang Weijie
|The effects of the “two-eight aging” and “short-aging” processes on the microstructure and room-temperature mechanical properties of Inconel 718 matrix and welding joints were studied. The casting structure morphology was obtained in the welding joints and the γ″ and γ′ reinforcing phases were precipitated in the dendrite crystals. The main dendrite was long and straight. However, the short and straight sub-dendrite crystals containing δ phase were precipitated on both sides of the main dendrites. The metastable γ″ phase was transformed into the stable δ phase because of the higher temperature of the “short-aging” process. As a result, the microhardness and the strength were lower than those of the “two-eight aging” process, and the elongation was not changed.
|Key words: high-temperature alloy electron beam welding aging treatment microstructure mechanical properties