Precipitation in 18 wt% Ni maraging steel of grade 350

Predicting microstructure and strength of maraging steels: Elemental optimisation

“…Similarly, in the Mar6-13 series (Fe Ni Mn Al Cu steels), Kapoor et al [7] reported that most of the Al and Cu atoms partition to the intermetallics, although no reverted austenite composition was reported for the conditions tested. As for molybdenum, it remains mostly in solid solution in during underaging, and later forming Mo-rich intermetallics during overageing [45,46]. These results allow us simplifying the description for by approximating it to an effective interdiffusion between and γ of Fe, Ni, Mn and Cr [47] Table 3, with .…”

“…Ti additions to the Fe Ni Ti Mo system promote the formation of rod-shaped Ni 3 Ti (η) in high-Ni containing steels, showing an apparent higher strength than the Al-containing steels at lower ageing temperatures [23,25]. Mo additions to this system in Co-free alloys promote the formation of the laves phase Fe 2 Mo; however, Tewari et al [45] showed that Fe 2 Mo intermetallics form at temperatures below 500°C and after 100 h of ageing due to the low diffusivity of Mo in Fe. Hence, they concluded that only the η particles contribute to the peak hardness in Fe 18Ni…”

Optimisation of Mechanical Properties of 18%Ni350 Grade Maraging Steel Using Novel Heat Treatment

“…from early 1960-s [3][4][5][6][7][8][9][10][11]. Mechanism and kinetics of precipitation depending on the chemical composition of maraging steel and parameters of heat treatment and in particular the early stages of precipitate strengthening were a subject of numerous research studies [12][13][14][15][16][17][18][19] and have not been fully understood till date. Description of these phenomena is complicated due to changes in chemical composition and crystallographic structure of strengthening nano-particles.…”

“…Unless marked otherwise, the alloy composition in this paper is given in wt.%. Tewari and others [12] conducted examinations of precipitates evolution in MS350 maraging steel using the small angle X-ray scattering and transmission electron microscopy techniques. The obtained results indicated the possibility of presence of two types of time-temperature-transformation (TTT) curves describing the process of nucleation and growth of precipitates: one for particles of ω phase and the second for Ni 3 Mo phase.…”

Comments onSmall-angle neutron scattering analysis of the precipitation behaviour in a maraging steelby Staron, Jamnig, Leitner, Ebner & Clemens (2003)

“…A variety of techniques have been employed to study the type, composition, size and volume fraction of the precipitates formed in maraging steels. These include direct methods, such as transmission electron microscopy (Vasudevan et al, 1990) and atom-probe ®eld ion microscopy (Sha et al, 1993a,b,c,d;Guo et al, 2003), and indirect methods, such as small-angle X-ray scattering (Tewari et al, 2000), small-angle neutron scattering (Servant & Bouzid, 1989) and Mo È ssbauer spectroscopy (Li & Yin, 1995). Recently, Staron et al studied the precipitation behaviour in a Cr-containing maraging steel using energy ®ltering transmission electron microcopy (EFTEM) and small-angle neutron scattering (SANS) (Staron et al, 2003).…”