Transmission Electron Microscopy Study of Strengthening Precipitates in 18% Ni Maraging Steel

Shimizu, K.; Okamoto, Hisaki

doi:10.2320/matertrans1960.12.273

Cited by 22 publications

(4 citation statements)

References 4 publications

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“…The tensile strength and hardness values lie on the bell-shaped curve, where the maximum values are obtained at a tempering temperature of around 500 °C. The strength and hardness increase at temperatures between 20 and 500 °C is caused by the formation of Ni 3 Ti and Ni 3 Mo precipitates, which are coherently embedded into the martensitic steel microstructure and distort the lattice around them [27]. In turn, the strength and hardness reduction at temperatures of 500 °C and higher is caused by the dissolution of those intermetallic phases and a transformation from the martensitic to an α-ferrite microstructure.…”

Section: Integration Of Heat Treatment Of 12709 Maraging Steel Into B...mentioning

confidence: 99%

An investigation of the influence of integration of steel heat treatment and brazing process on the microstructure and performance of vacuum-brazed cemented carbide/steel joints

et al. 2022

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Cemented carbides are commonly brazed to transformation hardening tool steels without taking a proper and adequate steel heat treatment into account. This publication shows the limits and possibilities of integrating a steel heat treatment, including a quenching process, into a vacuum brazing process. Therefore, copper-based filler metals are selected to ensure the steel component’s high and homogenous hardness and supply a high joint quality. In this context, the aimed steel hardness was chosen in the range between 400 and 440 HV1 based on industrial experiences. This specific hardness range for the steel component was set to avoid wear of machining tools in subsequent machining steps if the steel hardness is too high and to prevent wear and deformation of the tool itself in case of a steel hardness too low. When using the transformation hardening tool steel 1.2344, the obtained shear strength values did not exceed a threshold of 20 MPa which can be attributed to the required N2-quenching from brazing respectively solution annealing temperature. However, the steel components featured a hardness of 527.1 HV1 for the specimens brazed with pure copper at 1100 °C and 494.0 HV1 for those brazed with a CuGeNi filler metal at 1040 °C. This publication also shows an alternative route to manufacture long-lasting tools with a cemented carbide/steel joint by applying the difficult to wet and not well researched, but for many other reasons very suitable precipitation hardening maraging steel. Especially, the comparable low coefficient of thermal expansion (CTE) and the capability of the lath martensite to compensate large amounts of externally imposed stresses during the austenite-to-martensite transformation as well as the cooling rate independent of the hardening mechanism of the maraging steel and a pre-applied nickel coating including the corresponding diffusion processes are responsible for a sound joint with a shear strength > 300 MPa. Moreover, the subsequent tempering process at 580 °C for 3 h provides the maraging steel joining partner with a hardness of 426.6 ± 6.0 HV1.

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Section: Integration Of Heat Treatment Of 12709 Maraging Steel Into B...mentioning

confidence: 99%

An investigation of the influence of integration of steel heat treatment and brazing process on the microstructure and performance of vacuum-brazed cemented carbide/steel joints

et al. 2022

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“…Orientation relationship between b.c.c Fe matrix and h.c.p precipitates was determined as (0001) P //(011) M and[11][12][13][14][15][16][17][18][19][20] P //[11-1] M , with subscripts P and M denoting the precipitate and matrix, respectively. This is the common Burgers orientation relationship of the b.c.c-h.c.p precipitation system (Ref[25][26][27]. The second-phase precipitates demonstrate remarkable streak-…”

mentioning

confidence: 90%

Microstructure and Mechanical Properties of Mn-Containing Maraging Steels

Zargari

Nedjad

2015

J. of Materi Eng and Perform

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An attempt to the modification of the microstructure and mechanical properties of affordable, Mn-containing maraging alloys is reported. These alloys have demonstrated strong age hardening but suffered with premature intergranular brittleness despite their potential applications in tooling, dies, and machinery industries. An Fe-10Ni-6Mo-3Mn-1Ti (wt.%) alloy was prepared by vacuum melting and processed by homogenization (1250°C/48 h), cold rolling, solution annealing (950°C/1 h), and aging treatments (500°C/4 h). It presented tensile strength of about 2.65 GPa, a few percent of tensile elongation and a mixed ductile-brittle fracture mode. Transmission electron microscopy (TEM) revealed the precipitation of a nearly spherical phase. Crystal symmetry of the second phase precipitates was identified hexagonal closepacked corresponding reasonably to the Fe 2 Mo Laves phase having lattice parameters of a = 0.4745 and c = 0.7754 nm. Precipitation of a Mo-enriched second-phase particle was occasionally found at prior austenite grain boundaries but the pronounced grain boundary precipitation was never identified. Energyfiltering transmission electron microscopy using the Mo-M 4,5 post edge revealed remarkable segregation of Mo at grain boundaries.

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“…the sample aged at 460 o C. The corresponding SADPs show that most of the precipitates are η-Ni 3 (Mo,Ti) phase. It is known that the η-Ni 3 (Mo,Ti) phase preferentially nucleated at the tangles of dislocations [18,19] . Therefore, it is reasonably believed that an increase in dislocation density induced by ECAP deformation could promote the precipitation of the phase and their distribution.…”

Section: Microstructuresmentioning

confidence: 99%

Microstructures and Tensile Properties of Maraging Steel Processed by Equal-Channel Angular Pressing

Yang

Liu

et al. 2010

MSF

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An 18Ni (C-250) maraging steel was successfully processed by equal channel angular pressing (ECAP) for a single pass at room temperature. Microstructural observations showed that the martensite laths of 18Ni maraging steel were elongated to more narrow bands with a width of 100-200 nm after ECAP deformation. After ageing treatment, many nano-sized precipitates distributed uniformly within the refined martensite lathes. In comparison with the tensile strength (1940 MPa) of general used steel (solution + aging treatment), the tensile strength of the sample processed by ECAP and subsequent aging treatment was enhanced for more than 100 MPa (above 2050 MPa). The enhancement of tensile properties was attributed to microstructural refinement and uniformly distributed nano-precipitates.

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Transmission Electron Microscopy Study of Strengthening Precipitates in 18% Ni Maraging Steel

Cited by 22 publications

References 4 publications

An investigation of the influence of integration of steel heat treatment and brazing process on the microstructure and performance of vacuum-brazed cemented carbide/steel joints

An investigation of the influence of integration of steel heat treatment and brazing process on the microstructure and performance of vacuum-brazed cemented carbide/steel joints

Microstructure and Mechanical Properties of Mn-Containing Maraging Steels

Microstructures and Tensile Properties of Maraging Steel Processed by Equal-Channel Angular Pressing

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