固溶时效处理对激光粉末床熔融FeCoNi合金组织与性能的影响

doi:10.13251/j.issn.0254-6051.2025.02.019

摘要/Abstract

摘要： 研究了固溶和固溶时效处理对激光粉末床熔融FeCoNi中熵合金微观组织和力学性能的影响。结果表明,固溶态合金为BCC单相结构,固溶过程中条状熔池发生溶解,晶粒再结晶粗化。固溶+时效合金晶界处和晶内析出颗粒状Ni₃Fe相,其含量随固溶温度的升高而减少,900 ℃固溶+470 ℃时效使合金晶粒尺寸由固溶态4.16 μm细化为2.43 μm。固溶处理过程中胞状结构消失和残余应力释放,使900 ℃固溶态合金硬度降低至314 HV0.2,抗拉强度为709 MPa。固溶+时效处理后基体析出Ni₃Fe金属间化合物,使得FeCoNi合金强度提升,900 ℃固溶+470 ℃时效合金的硬度为508 HV0.2,抗拉强度为1238 MPa,合金强度主要由析出强化和细晶强化贡献;但是晶界析出相附近的位错堆积会产生应力集中,导致FeCoNi中熵合金塑性下降。

关键词: 中熵合金FeCoNi, 激光粉末床熔融, 固溶时效, 组织, 力学性能

Abstract: Effects of solution treatment and solution treatment+aging on microstructure and mechanical properties of the FeCoNi medium entropy alloy prepared by laser powder bed fusion were investigated. The results show that the microstructure of solution treated alloy is BCC single-phase structure, and during the solution process, the strip-shaped molten pool dissolves and the grains undergo recrystallization and coarsening. Granular Ni₃Fe phase precipitates at the grain boundaries and within the grains of the solution treated and aged alloy, and its content decreases with the increase of solution temperature. Solution treatment at 900 ℃ and aging at 470 ℃ refine the grain size of the alloy from 4.16 μm(solution treated) to 2.43 μm. During the solution treatment process, the disappearance of cellular structure and the release of residual stress result in a decrease in the hardness of the 900 ℃ solution treated alloy to 314 HV0.2 and a tensile strength of 709 MPa. After solution treatment and aging, Ni₃Fe intermetallic compounds precipitate from the matrix, which enhances the strength of the FeCoNi alloy. The hardness of FeCoNi alloy after solution treatment at 900 ℃ and aging at 470 ℃ is 508 HV0.2, and the tensile strength is 1238 MPa. The alloy strength is mainly contributed by precipitation strengthening and grain refinement strengthening. However, the accumulation of dislocations near the grain boundary precipitates can cause stress concentration, leading to a decrease in the plasticity of the FeCoNi medium entropy alloy.

Key words: FeCoNi medium entropy alloy, laser powder bed fusion, solution treatment and aging, microstructure, mechanical properties

中图分类号:

TG456.7

叶国晨, 夏忠虎. 固溶时效处理对激光粉末床熔融FeCoNi合金组织与性能的影响[J]. 金属热处理, 2025, 50(2): 121-127.

Ye Guochen, Xia Zhonghu. Effect of solution treatment and aging on microstructure and properties of laser powder bed fused FeCoNi alloy[J]. Heat Treatment of Metals, 2025, 50(2): 121-127.

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