IN718高温合金因其优异的抗氧化性和抗热腐蚀性、良好的疲劳性能、组织稳定性及安全可靠性等综合性能,广泛应用于航空航天、核工业等领域,是新一代先进航空发动机热端构件不可替代的材料之一。激光粉末床熔融(laser powder bed fusion,L...IN718高温合金因其优异的抗氧化性和抗热腐蚀性、良好的疲劳性能、组织稳定性及安全可靠性等综合性能,广泛应用于航空航天、核工业等领域,是新一代先进航空发动机热端构件不可替代的材料之一。激光粉末床熔融(laser powder bed fusion,LPBF)技术作为近年来发展迅速的新型快速成形技术,突破传统成形技术和结构设计束缚,实现复杂薄壁构件的一步激光近净成形,展现出广阔的应用前景。然而在激光增材制造成形过程中,薄壁表面的激光输入能量较大,易出现翘曲变形和裂纹,严重影响其服役性能。针对以上问题,本工作概述LPBF技术的工作原理及研究动态,系统分析LPBF成形IN718高温合金薄壁的跨尺度微观组织演化特征及析出相演变行为,重点梳理缺陷萌生和扩展机制,从优化结构设计、激光成形工艺参数、合金成分等多方面对缺陷抑制进行归纳,分析探讨IN718高温合金薄壁室温与高温力学性能的强化机制。最后,总结LPBF成形高温合金薄壁存在严苛环境下关键性能不足等问题并展望未来发展方向,其中包括:建立适合高温合金薄壁的激光成形工艺数据库;研究LPBF成形高温合金薄壁凝固缺陷形成及调控新方法;优化高性能高温合金薄壁构件材料化学成分。展开更多
0.05 wt.%Y was incorporated into IN718 alloy powders,and specimens were fabricated using selective laser melting(SLM)technology.High-temperature tensile tests were then performed at 650℃on both the as-built and heat-...0.05 wt.%Y was incorporated into IN718 alloy powders,and specimens were fabricated using selective laser melting(SLM)technology.High-temperature tensile tests were then performed at 650℃on both the as-built and heat-treated specimens.The results revealed that both the as-built and heat-treated 0.05Y-IN718 specimens exhibit a slight increase in tensile strength compared to 0Y-IN718 specimen,attributed to the formation of Y-O and Y-Al-O nano-oxides.Notably,the ductility of 0.05Y-IN718 alloy was largely improved in as-built state,but only marginally improved in heat-treated state.Previous research suggests that the improved ductility can be ascribed to Y effect on grain boundary purification and alterations in the morphology of carbides andδphase.However,an in-depth analysis was conducted based on the scanning/transmission electron microscope and density functional theory results and demonstrated that it is Y segregation in the Laves/γmatrix interface that actually plays the vital role for enhancing interfacial bonding.Hence,the extremely fast cooling rate during SLM processing facilitates mass accumulation of Y in the interdendritic region or cellular wall,achieving a large improvement in the ductility.展开更多
文摘IN718高温合金因其优异的抗氧化性和抗热腐蚀性、良好的疲劳性能、组织稳定性及安全可靠性等综合性能,广泛应用于航空航天、核工业等领域,是新一代先进航空发动机热端构件不可替代的材料之一。激光粉末床熔融(laser powder bed fusion,LPBF)技术作为近年来发展迅速的新型快速成形技术,突破传统成形技术和结构设计束缚,实现复杂薄壁构件的一步激光近净成形,展现出广阔的应用前景。然而在激光增材制造成形过程中,薄壁表面的激光输入能量较大,易出现翘曲变形和裂纹,严重影响其服役性能。针对以上问题,本工作概述LPBF技术的工作原理及研究动态,系统分析LPBF成形IN718高温合金薄壁的跨尺度微观组织演化特征及析出相演变行为,重点梳理缺陷萌生和扩展机制,从优化结构设计、激光成形工艺参数、合金成分等多方面对缺陷抑制进行归纳,分析探讨IN718高温合金薄壁室温与高温力学性能的强化机制。最后,总结LPBF成形高温合金薄壁存在严苛环境下关键性能不足等问题并展望未来发展方向,其中包括:建立适合高温合金薄壁的激光成形工艺数据库;研究LPBF成形高温合金薄壁凝固缺陷形成及调控新方法;优化高性能高温合金薄壁构件材料化学成分。
基金support of the National Natural Science Foundation of China(No.52101068)China Postdoctoral Science Foundation(No.2022T150342)+2 种基金Postdoctoral International Exchange Program(No.YJ20210129)support of Shuimu Tsinghua program(No.2020SM100)supported by the Advanced Computing Center of Yunnan University.
文摘0.05 wt.%Y was incorporated into IN718 alloy powders,and specimens were fabricated using selective laser melting(SLM)technology.High-temperature tensile tests were then performed at 650℃on both the as-built and heat-treated specimens.The results revealed that both the as-built and heat-treated 0.05Y-IN718 specimens exhibit a slight increase in tensile strength compared to 0Y-IN718 specimen,attributed to the formation of Y-O and Y-Al-O nano-oxides.Notably,the ductility of 0.05Y-IN718 alloy was largely improved in as-built state,but only marginally improved in heat-treated state.Previous research suggests that the improved ductility can be ascribed to Y effect on grain boundary purification and alterations in the morphology of carbides andδphase.However,an in-depth analysis was conducted based on the scanning/transmission electron microscope and density functional theory results and demonstrated that it is Y segregation in the Laves/γmatrix interface that actually plays the vital role for enhancing interfacial bonding.Hence,the extremely fast cooling rate during SLM processing facilitates mass accumulation of Y in the interdendritic region or cellular wall,achieving a large improvement in the ductility.
