Evidence of austenite memory in PH 15-5 and assessment of its formation mechanism

Brandl, Dominik; Lukas, Marina; Stockinger, Martin; Ploberger, Sarah; Ressel, Gerald

doi:10.1016/j.matdes.2019.107841

Cited by 21 publications

(8 citation statements)

References 40 publications

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“…The almost identical appearance of the martensitic structure before and after intercritical annealing hints the occurrence of the so‐called austenite memory effect, i.e., reversing austenite inherits the morphology and orientation of the prior austenite. [ 43–48 ] Furthermore, the austenite memory effect can be directly observed in the HT‐EBSD results where the orientation of reverted austenite (Figure 4d) appears to be identical compared to austenite formed during intercritical annealing (Figure 4b). Nevertheless, it should be taken into account that the austenite memory effect was observed on a free surface where the mechanical constraints are different compared to bulk regions.…”

Section: Discussionmentioning

confidence: 93%

In Situ Observations of the Microstructural Evolution during Heat Treatment of a PH 13‐8 Mo Maraging Steel

et al. 2023

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The standard heat treatment of PH 13‐8 Mo maraging steels consists of solution annealing and subsequent aging. Herein, it is investigated how an additional intercritical annealing step prior to aging affects the microstructure, and, consequently, the mechanical properties of a PH 13‐8 Mo maraging steel. In situ techniques by means of high‐temperature electron backscatter diffraction and high‐temperature X‐ray diffraction are applied to study the microstructural changes during intercritical annealing and subsequent aging. In addition, high‐resolution investigation methods, such as transmission electron microscopy and atom probe tomography supplemented by transmission Kikuchi diffraction, are used for an in‐depth characterization of the microstructure. The results reveal that a diffusion‐controlled martensite to austenite transformation accompanied by partitioning of the substitutional atoms Cr, Ni, and Mo takes place during intercritical annealing. As a result of partitioning during intercritical annealing, an inhomogeneous distribution of Ni remains in the microstructure after the martensitic transformation. Consequently, the formation of reverted austenite is facilitated during subsequent aging due to existing Ni‐enriched zones in martensite. Since the fracture toughness is significantly enhanced compared to the standard heat treatment, it is suggested that this improvement is related to the increased phase fraction of reverted austenite.

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Section: Discussionmentioning

confidence: 93%

In Situ Observations of the Microstructural Evolution during Heat Treatment of a PH 13‐8 Mo Maraging Steel

et al. 2023

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“…Figure 9h is the (100) pole figure that combined the martensite and reverted austenite, in which red color represents the pole point of the reverted austenite and the pole point of martensite was marked with black color. The reflexes of reverted austenite inside circles of martensite are a characteristic of (100) pole figures showing the K-S orientation relationship [46,47]. It implies that the reversed austenite had the same orientation with the surrounding martensite variants.…”

Section: Discussionmentioning

confidence: 99%

Temperature Dependent Phase Transformation Kinetics of Reverted Austenite during Tempering in 13Cr Supermartensitic Stainless Steel

Zhang

Yin

et al. 2019

Metals

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The formation and growth kinetics of the reverted austenite during tempering in 13Cr supermartensitic stainless steel were investigated by a combination X-ray diffraction (XRD), transmission electron microscopy (TEM) and electron backscatter diffraction (EBSD) in a scanning electron microscope (SEM). The reverted austenite precipitated at the martensite blocks, sub-blocks, laths and grain boundaries. The growth kinetics was established by Johnson-Mehl-Avrami (JAM) kinetics equation according to the volume fraction of the equilibrium reverted austenite at room temperature. The Avrami exponent value is 0.5, and the activation energy was estimated to be 369 kJ/mol, the kinetic model indicates that the mechanism of reverted austenite is diffusion-controlled and the growth of reverted austenite closely relies on the diffusion of the nickel (Ni) element. The experimental measured orientations of the reverted austenite are in good agreement with the theoretical ones, implying that the reverted austenite has the same orientation with the surrounding martensite, which meets the Kurdjumov–Sachs (K-S) orientation relationship. The orientation relationships minimize the strain energy of the phase transformation by reducing the crystallographic mismatch between phases.

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“…It is well known that dislocations can pass through precipitates by cutting or bypassing the mechanism, and the mechanical properties are affected by the interaction between precipitates and dislocations, which is closely related to the size of precipitates. Furthermore, various types of strengthening phases in the existing representative PHSS have been investigated [ 101 , 102 , 103 ], such as B2-NiAl particles in PH13-8Mo steel [ 104 , 105 ], the Cu-rich cluster in PH17-4 and PH15-5 steels [ 83 , 106 , 107 , 108 ], and Ni 3 Ti precipitates in Custom 465 steel [ 64 ], etc. [ 109 , 110 ].…”

Section: Microstructure and Properties After Typical Heat Treatment P...mentioning

confidence: 99%

Recent Advances on Composition-Microstructure-Properties Relationships of Precipitation Hardening Stainless Steel

et al. 2022

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Precipitation hardening stainless steels have attracted extensive interest due to their distinguished mechanical properties. However, it is necessary to further uncover the internal quantitative relationship from the traditional standpoint based on the statistical perspective. In this review, we summarize the latest research progress on the relationships among the composition, microstructure, and properties of precipitation hardened stainless steels. First, the influence of general chemical composition and its fluctuation on the microstructure and properties of PHSS are elaborated. Then, the microstructure and properties under a typical heat treatment regime are discussed, including the precipitation of B2-NiAl particles, Cu-rich clusters, Ni3Ti precipitates, and other co-existing precipitates in PHSS and the hierarchical microstructural features are presented. Next, the microstructure and properties after the selective laser melting fabricating process which act as an emerging technology compared to conventional manufacturing techniques are also enlightened. Thereafter, the development of multi-scale simulation and machine learning (ML) in material design is illustrated with typical examples and the great concerns in PHSS research are presented, with a focus on the precipitation techniques, effect of composition, and microstructure. Finally, promising directions for future precipitation hardening stainless steel development combined with multi-scale simulation and ML methods are prospected, offering extensive insight into the innovation of novel precipitation hardening stainless steels.

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Evidence of austenite memory in PH 15-5 and assessment of its formation mechanism

Cited by 21 publications

References 40 publications

In Situ Observations of the Microstructural Evolution during Heat Treatment of a PH 13‐8 Mo Maraging Steel

In Situ Observations of the Microstructural Evolution during Heat Treatment of a PH 13‐8 Mo Maraging Steel

Temperature Dependent Phase Transformation Kinetics of Reverted Austenite during Tempering in 13Cr Supermartensitic Stainless Steel

Recent Advances on Composition-Microstructure-Properties Relationships of Precipitation Hardening Stainless Steel

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