采用无坩埚感应熔炼超声气体雾化法(EIGA) +热等静压工艺制备的大尺寸粉末冶金Inconel 718合金坯料中存在大量原始颗粒边界，恶化了材料的力学性能。本工作通过特殊高温热处理对合金坯料进行组织修复，观察了其显微组织、测试了其力学性能。结果表明，试验型包套成形合金的力学性能与锻件相当。采用相同热等静压工艺成形大型复杂结构件，由于屏蔽效应、制备工艺参数未完全优化等原因，粉末冶金结构件中出现大量原始颗粒边界(PPBs)，恶化了Inconel 718合金的拉伸塑性和冲击性能。特殊高温热处理可以有效消除合金坯料中的PPBs，增加颗粒间结合强度，改善合金性能。热等静压+特殊高温热处理可以作为粉末冶金Inconel 718大型复杂结构件成形工艺，结构件本体力学性能与锻件相当。

Inconel 718 alloy is widely used in aeronautical fields owing to its excellent mechanical properties and high-temperature resistance. Hot isostatic pressing (HIPing) is a powder metallurgy (PM) processing technology that produces near or net-shape components and solves the problems of macro-segregation and microstructure inhomogeneity. However, the application of PM Inconel 718 alloys has been limited by prior particle boundaries (PPBs), which can negatively impact mechanical properties, such as elongation at elevated temperatures and impact properties. To address this issue, the formation of PPBs can be suppressed during HIPing, or they can be eliminated through subsequent processing. Pre-alloyed powder of Inconel 718 was prepared using the electrode induction melting gas atomization (EIGA) method, and PM Inconel 718 alloys were prepared through the HIPing route. The resulting compacts were subjected to special high-temperature heat treatment, and their mechanical properties were tested. The mechanical properties of PM Inconel 718 test bars were found to be comparable to those of the wrought version of the alloy. However, large and complex components of PM Inconel 718 can contain undesirable PPBs due to mold shielding and insufficient degassing, resulting in poor ductility and impact properties after standard heat treatment. Special high-temperature heat treatment can effectively eliminate the PPBs in the compacts, leading to a substantial improvement in tensile ductility and impact properties. This improvement makes it possible to prepare large and complex components through HIPing with improved mechanical properties.