Inverse Martensitic α → γ Transformation in Nanostructured Maraging Steels

Makhneva, T. M.; Sukhikh, A. A.; Дементьев, В. Б.

doi:10.1007/s11041-017-0174-1

Cited by 7 publications

(4 citation statements)

References 1 publication

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“…Enrichment of austenite with nickel in the two-phase region occurs in the steel under study, both in the presence of liquation [8] and without it, stabilizing the γ-phase [11]. This is also evidenced by the data of [7], in which the morphology study of α→γ-transformation in massive martensite carried out by V.I.…”

Section: Resultsmentioning

confidence: 74%

On the Chemical Heterogeneity of Austenite in Maraging Steel

Makhneva¹

2022

Materials Research Proceedings

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Abstract. The change of Ni-, Cr-, Cu- contents in maraging steel composition occurring on heating in the subcritical and intercritical interval has been studied by the X-ray spectral microanalysis. Heating in the temperature range from 490 to 550C has resulted in increasing of Ni- Cu- concentrations in the 1iquation austenite when the latter is present in the steel structure as a consequence of several reasons (the large ingot, low level of forging reduction ratio, etc.). The significant enrichment of surface layers of austenite inclusions may probably occur if there are great differences between interphase and intraphase diffusion rates. By varying the thermal treatment and thus the Ni-diffusion in austenite it is possible to create austenite layers with different Ni-contents within a grain or massive martensite and it is also possible to control the material properties.

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Section: Resultsmentioning

confidence: 74%

On the Chemical Heterogeneity of Austenite in Maraging Steel

Makhneva¹

2022

Materials Research Proceedings

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“…The austenite formed during the ageing process is known as inverse or reverse austenite. The amount of this austenite formed during ageing increases with higher ageing temperatures and longer ageing times [2,16]. The formation of reverse austenite is due to the matrix being enriched with elements that stabilise austenite [17], such as those resulting from the partial dissolution of Ni 3 (Ti, Mo) and the formation of Fe 2 Mo [18].…”

Section: Introductionmentioning

confidence: 99%

The Effect of Selective Laser Melting Fabrication Parameters on the Tensile Strength of an Aged New Maraging Steel Alloy with 8% Cr, Reduced Ni Content (7%), and No Co or Mo

Pérez-Gonzalo,

González-Pociño,

Alvarez-Antolin

et al. 2023

Materials

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The aim of this paper was to optimise the manufacturing parameters of a new maraging steel alloy with 8% Cr, reduced Ni content (7%), and no Co or Mo. This alloy was developed by ArcelorMittal and its trade name is LeanSi. The alloy was produced using the selective laser melting (SLM) process. In the as-built state, the microstructure of the alloy was fully martensitic. The optimisation of the manufacturing parameters was determined via a multivariate factorial design of experiments including 12 experiments and three factors. The factors (i.e., the fabrication parameters) analysed were laser power, scanning speed, and hatch distance. The objective was to eliminate porosity and maximise density. It was concluded that, to achieve this, the laser power should be set at 250 W, the scanning speed at 1000 mm/s, and the hatch distance at 80 microns. The porosity obtained under these manufacturing parameters was 0.06 ± 0.03% with a confidence level of 95%. If these manufacturing parameters were modified, the material exhibited a defective interlayer bond with the formation of “balling” and high porosity. The tensile specimens tested in the as-built state showed plastic deformation. However, all the aged specimens showed brittle fracture behaviour, evidenced by the presence of very small micro-cavities (where the fracture energy consumed was very small) and small cleavage planes. The specimens produced with the manufacturing parameters at their optimum levels and aged at 480 °C for 2 h achieved tensile strength values that averaged 1430 MPa. The porosity of these specimens was reduced by more than 85%. Reverse austenite was detected at ageing temperatures of 540 °C upwards.

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“…The austenite formed during aging is called reverse austenite. The percentage of this austenite increases with higher temperatures and longer aging times [18]. The formation of reverse or inverse austenite is a consequence of the enrichment of the austenite in stabilizing elements [19].…”

Section: Introductionmentioning

confidence: 99%

Analysis of a Double Aging Process in a Maraging 300 Steel Fabricated by Selective Laser Melting, Using the Design of Experiments Technique

Pérez-Gonzalo,

González-Pociño,

Alvarez-Antolin

et al. 2023

Metals

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This study aims to optimize the aging treatment of a maraging 300 steel, without prior austenitizing, manufactured by the selective laser melting (SLM) technique. The study includes the analysis of a double aging process. In addition, the impact of the aging treatment on corrosion resistance in 3.5 wt.% NaCl solution was analyzed. The research technique followed was a factorial design of experiments with three factors and two levels, performing one replicate of each experiment. The results show that excellent mechanical properties can be achieved by omitting the solubilization treatment prior to aging. The highest hardness and tensile strength were achieved by performing a double aging at 460 °C for 8 h. Under these conditions, the maximum hardness exceeded 615 HV and the tensile strength was over 2140 MPa. Aging at 520 °C caused the formation of reverse austenite. The aging temperature was the only factor that had a significant effect on the formation of reverse austenite. It should be noted that the holding time at this temperature did not have a significant effect. The corrosion resistance, in 3.5 wt.% NaCl aqueous solution, increased in the aged samples compared to the as-printed sample. Samples overaged at 520 °C showed the best corrosion resistance. It can be concluded that the predominant cathodic reaction taking place is the reduction of oxygen dissolved in the electrolyte.

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Inverse Martensitic α → γ Transformation in Nanostructured Maraging Steels

Cited by 7 publications

References 1 publication

On the Chemical Heterogeneity of Austenite in Maraging Steel

On the Chemical Heterogeneity of Austenite in Maraging Steel

The Effect of Selective Laser Melting Fabrication Parameters on the Tensile Strength of an Aged New Maraging Steel Alloy with 8% Cr, Reduced Ni Content (7%), and No Co or Mo

Analysis of a Double Aging Process in a Maraging 300 Steel Fabricated by Selective Laser Melting, Using the Design of Experiments Technique

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