This study investigates the effects of a step aging treatment on 18Ni300 maraging steel aiming to improve ductility while retaining ultra-high strength. The step aging treatment effectively controls the morphology, volume fraction, and size of precipitates and the reversed austenite. The first-stage aging at 480 °C promotes the nucleation of nano-sized η-Ni3Ti precipitates, while the second-stage aging at 560 °C induces the formation of the Laves-Fe2Mo phase and thin-film reversed austenite. Compared with single-stage peak aging, the sample aged at 480 °C for 3 h followed by 560 °C for 1 h exhibited a significant increase in elongation from 3.12% to 6.01%, with a moderate reduction in strength. This enhancement is mainly attributed to the ductility-enhancing effect of thin-film reversed austenite.
FuHXieLWangX, et al.Fracture mechanism and model of 18Ni maraging steel. Mater Sci Technol2020; 36: 894–898.
2.
JacobKYadavDDixitS, et al.High pressure torsion pr ocessing of maraging steel 250: microstructure and mechanical behaviour evolution. Mater Sci Eng A2021; 802: 140665.
3.
LiuXZhangMZhangK, et al.Regulating the precipitation-free zone and nano-precipitation phase by cyclic solution treatment in 2.3GPa maraging steel. Mater Charact2025; 229: 115522.
4.
HuangZ. Creep-resistant aeroengine shaft steels: precipitates and consequences. Mater Sci Technol2019; 35: 1405–1415.
5.
WangSZhaoYWenP, et al.Precipitate evolution in an ultrahigh-strength, carbon-impurity-enhanced maragin g steel manufactured via laser powder bed fusion. Acta Mater2025; 300: 121455.
6.
ZhuFYinYFFaulknerRG. Microstructural control of maraging steel C300. Mater Sci Technol2011; 27: 395–405.
7.
PerelomaEVShekhterAMillerMK, et al.Ageing behaviour of an Fe–20Ni–1.8Mn–1.6Ti–0.59Al (wt%) maraging alloy: clustering, precipitation and harden ing. Acta Mater2004; 52: 5589–5602.
8.
HuangFChengZLiD, et al.Grain refinement and microstructur al evolution in cobalt-saving 18Ni (300) maraging steel via cold deformation-cyc lic solution treatment. Mater2025; 18: 2947.
9.
YangBLiuBLuoZ, et al.Design and control the selection of mart ensitic variant to simultaneously improve strength and toughness of low-carbon mart ensitic steel. Mater Charact2024; 218: 114540.
10.
HuangJNTangZYDingH, et al.Combining a n ovel cyclic pre-quenching and two-stage heat treatment in a low-alloyed TRIP-aided steel to significantly enhance mechanical properties through microstructural refinement. Mater Sci Eng A2019; 764: 138231.
11.
RohitBMuktinutalapatiNR. Austenite reversion in 18% Ni maraging steel and i ts weldments. Mater Sci Technol2018; 34: 253–260.
12.
ChenWLuanJHXuL, et al.Reversed austenite in additively manufactured martensitic stainless steel. Mater Sci Eng A2022; 834: 142597.
13.
ZhangYLiYDengX. Effect of aging temperature on the microstructural evol ution and mechanical properties of 18Ni (200) maraging steel. Mater Sci Eng A2025; 919: 147497.
14.
HuangFChengZZhangD, et al.A novel process for simultaneously improving the strength and plasticity of 18Ni(350) maraging steel. J Mater Res Technol2024; 33: 6144–6156.
15.
XuDChenYQiZ, et al.Heterogeneous nucleation of Ni3Ti by Mo-enriched particles enhances strength and fracture toughness of maraging steel. J Mater Res Technol2025; 35: 4779–4791.
16.
ZhangHJiXMaD, et al.Effect of agi ng temperature on the austenite reversion and mechanical properties of a Fe–10Cr–1 0Ni cryogenic maraging steel. J Mater Res Technol2021; 11: 98–111.
17.
ShanZLiuSYeL, et al.Mec hanism of precipitate microstructure affecting fatigue behavior of 7020 aluminum alloy. Mater2020; 13: 3248.
18.
CarvalhoLGDAndradeMSPlautRL, et al.A dilatometr ic study of the phase transformations in 300 and 350 maraging steels during contin uous heating rates. Mater Res2013; 16: 740–744.
19.
ZhouXJiaCShiX, et al.Toughness degradatio n caused by reversed austenite formed during over-aging treatment in a 2.3GPa m araging steel. J Mater Res Technol2025; 38: 331–342.
20.
JacobKRoyAGururajanMP, et al.Effect of dislocation network on pre cipitate morphology and deformation behaviour in maraging steels: modelling and e xperimental validation. Materialia2022; 21: 101358.
21.
MeiXYanYFuH, et al.Effect of aging temperature o n microstructure evolution and strengthening behavior of L-PBF 18Ni(300) maraging steel. Addit Manuf2022; 58: 103071.
22.
YangZZhangJYuL, et al.Effects of agin g time on the microstructure and mechanical properties of 18Ni200 maraging steel. J Mater Res Technol2025; 37: 368–379.
23.
TalonenJHänninenH. Formation of shear bands and strain-induced martensite du ring plastic deformation of metastable austenitic stainless steels. Acta Mater2007; 55: 6108–6118.
24.
HuJZhouYYinL, et al.Effect of aging temperature on microstructure and properties of maraging steel for ultra-low temperature. J Mater Res Technol2025; 37: 2953–2964.
25.
FeitosaALMRibamarGGEscobarJ, et al.Precipitation and reverted austenite formation in mara ging 350 steel: competition or cooperation?Acta Mater2024; 270: 119865.
26.
LiuYZhangHHuaL, et al.Deformation behavi or and microstructural evolution of Ti-6Al-4V alloy under compression with confini ng pressure. Int J Plast2026; 198: 104610.
NiuMZhouGWangW, et al.Precipitate evolutio n and strengthening behavior during aging process in a 2.5GPa grade maraging steel. Acta Mater2019; 179: 296–307.
29.
RackHJKalishD. The strength and fracture toughness of 18 Ni (350) maraging steel. Metall Trans1971; 2: 3011–3020.
30.
Galindo-NavaEIRivera-Díaz-Del-CastilloPEJ. A model for the microstructure b ehaviour and strength evolution in lath martensite. Acta Mater2015; 98: 81–93.
31.
ArdellAJ. Precipitation hardening. Metall Trans A1985; 16: 2131–2165.
