Influence of aging temperature on the microstructure and mechanical property in γˊ-Ni3(Ti, Al) precipitation-strengthened Invar alloy

IF 7 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Science and Engineering: A Pub Date : 2025-10-11 DOI:10.1016/j.msea.2025.149236

Seok-Hwan Hong , Jaejun Jeong , I-Jun Ro , Jeongseok Kim , Ho Hyeong Lee , Se-Ho Kim , Yoon-Uk Heo , Heung Nam Han , Dong-Woo Suh

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引用次数: 0

Abstract

This study investigates the effect of aging temperature on the impact toughness of a γʹ-Ni₃(Ti, Al) precipitation-strengthened Fe-38.7Ni-3.5Co-1.0Ti-1.2Al (wt.%) Invar alloy. The formation of coherent γʹ precipitates via discontinuous precipitation (DP) along grain boundaries and continuous precipitation (CP) within grain interiors was promoted with aging temperature ranging from 500 °C to 600 °C. These precipitates significantly improved strength without severely compromising ductility. Remarkably, the alloy retained high impact toughness (∼350 J) up to 550 °C; however, a sharp drop to ∼200 J occurred after aging at 600 °C. Microstructural analysis revealed that the hardness difference between the DP and CP regions intensified at aging temperature of 600 °C, facilitating localized strain accumulation and void formation along DP interfaces during impact test. This transition of primary energy absorption mechanism – from plastic deformation to void-driven fracture - was identified as the cause of impact toughness degradation. The findings highlight a critical trade-off between strength and impact toughness in precipitation-hardened Invar alloys and offer new insight into their microstructural design for structural applications.

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时效温度对γ -Ni3（Ti, Al）析出强化Invar合金组织和力学性能的影响

研究了时效温度对γ′-Ni3（Ti, Al）析出强化Fe-38.7Ni-3.5Co-1.0Ti-1.2Al (wt.%) inar合金冲击韧性的影响。时效温度在500 ~ 600℃范围内促进了沿晶界不连续析出（DP）和晶粒内部连续析出（CP）的形成。这些析出物显著地提高了强度，而不会严重损害延展性。值得注意的是，该合金在高达550°C时仍保持高冲击韧性（~ 350 J）；然而，在600°C老化后急剧下降到~ 200 J。显微组织分析表明，在600℃时效温度下，DP区和CP区的硬度差异加剧，有利于冲击试验过程中DP界面的局部应变积累和空洞形成。这种主要能量吸收机制的转变——从塑性变形到空洞驱动断裂——被认为是导致冲击韧性退化的原因。研究结果强调了沉淀硬化Invar合金强度和冲击韧性之间的关键权衡，并为其结构应用的显微组织设计提供了新的见解。

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来源期刊

Materials Science and Engineering: A 工程技术-材料科学：综合

CiteScore

11.50

自引率

15.60%

发文量

1811

审稿时长

31 days

期刊介绍： Materials Science and Engineering A provides an international medium for the publication of theoretical and experimental studies related to the load-bearing capacity of materials as influenced by their basic properties, processing history, microstructure and operating environment. Appropriate submissions to Materials Science and Engineering A should include scientific and/or engineering factors which affect the microstructure - strength relationships of materials and report the changes to mechanical behavior.