Influence of reverted austenite on static and dynamic mechanical properties of a PH 13-8 Mo maraging steel

Predicting microstructure and strength of maraging steels: Elemental optimisation

“…This process is consistent with experimental evidence showing that γ-stabilising elements partition into the lath boundaries [37]. Moreover, the growth of reverted austenite is controlled by the matrix as individual nuclei will grow around the α′ laths [14].…”

“…It is worth noting that although the carbon content in most of the steels tested is low, a significant amount of carbides could still be present; this would promote a competition between carbide and intermetallic strengthening. Nevertheless, Schintzer et al [14,19] and Leitner et al [3] did not report carbide formation in PH13 8Mo for the ageing conditions employed in this work. Similarly, Zhu et al [20] did not measure any carbon content in C300.…”

“…However, small variations in d lath have been observed in a variety of maraging steels with different Ni and Mn content, even for tempered conditions [14,20,25,26,39]; this behaviour can be due to the relatively low lattice distortion and high solubility of substitutional atoms in Fe with respect to C atoms; hence, based on these experimental results, it is considered that d lath = 250 nm remains constant for all steels tested. For this case, ρ ≈ 3.6 × 10 14 m −2 , being this prediction consistent with experimental estimations in a stainless maraging steel [40].…”

“…Reverted austenite nucleates at the lath and PAG boundaries [41], and growth is diffusion-controlled at a given ageing temperature [12,14]. Moszner et al [42] have suggested that austenite formation in Fe…”

“…Such could provide direct links between the microstructure and mechanical properties for different compositions and heat treatments. A key reason for this is the lack of a description for the martensitic matrix, as its hierarchical structure strongly controls microstructure evolution [6,12,14]: a high dislocation density in the laths accelerates precipitation nucleation, whereas the segregation of γ-stabilising elements into the lath boundaries determines the morphology and kinetics of the reverted austenite [14][15][16].…”