Multicomponent Precipitation and Strengthening in Intermetallic-Strengthened Alloys

Abstract

Advanced structural materials with superior mechanical properties are of technological importance for industrial applications. Multicomponent precipitation provides a potential approach for designing high-performance alloys and has been receiving increasing attention from both academia and industry. In this Perspective, we highlight the recent advances and future perspectives in multicomponent-precipitation-strengthened alloys, including multicomponent steels, superalloys, and high-entropy alloys. The emphasis is placed on the unique microstructural features and challenges of multicomponent precipitation as well as their impacts on the strengthening behavior. Finally, future research areas for this class of materials are critically discussed.

Influence of Mo Content on the Precipitation Behavior of 13Ni Maraging Ultra-High Strength Steels

“…Alloys with higher titanium contents preferentially form Ni 3 Ti, while alloys with higher molybdenum contents preferentially form Ni 3 Mo. This is consistent with the literature, which explains why the Ni 3 Ti phase is preferentially formed over Ni 3 Mo, due to the higher interaction energy between nickel and titanium and the low diffusivity of molybdenum in the matrix [8,27].…”

“…Recent studies have also observed that Laves phases not only form after but also at the interface of Ni 3 Ti and Ni 3 Mo precipitates with the matrix [8,16,27]. Our results can reinforce this, since we found an orientation relationship between the Laves phase and Ni 3 Mo, given by (01 Regarding Ni 3 Ti and Ni 3 Mo phases, most studies on maraging steels have consistently reported the presence of Ni 3 Ti in the early stages of aging and have indicated that molybdenum only begins to participate in the phase formation for longer aging times [8,16,27]. Furthermore, it is progressively established that Ni 3 Ti-type precipitates exhibit needle-like morphology.…”

“…The matrix exhibits a high density of dislocations (usually greater than 10 11-12 cm −2 ) and dislocation tangles, both of which act as nucleation sites for precipitates during the early stages of aging [3,9]. Figure 1b shows the illustration of these precipitates formed during aging, which usually present with spherical or needle-life morphology [21,27]. After aging, the austenite grain size remained the same, while the martensite laths increased in size, and dislocations disappeared with increasing aging time.…”

“…There is a consensus among the various authors who have worked with maraging steels that the Ni 3 Ti and Ni 3 Mo precipitates form before Fe 2 Mo and Fe 2 Ti precipitates, as they are more stable [4,9,20]. Recent studies have also observed that Laves phases not only form after but also at the interface of Ni 3 Ti and Ni 3 Mo precipitates with the matrix [8,16,27]. Our results can reinforce this, since we found an orientation relationship between the Laves phase and Ni 3 Mo, given by (01 Regarding Ni 3 Ti and Ni 3 Mo phases, most studies on maraging steels have consistently reported the presence of Ni 3 Ti in the early stages of aging and have indicated that molybdenum only begins to participate in the phase formation for longer aging times [8,16,27].…”

“…According to precipitation hardening mechanisms models, these very small precipitates, coherent and/or semi-coherent with the matrix, are sheared by the dislocation in their slip planes during the plastic deformation of the material. This leads to a high hardness value, and the maximum value of the hardness/mechanical strength versus the aging time curve (peak hardness) occurs when the volume fraction of precipitates reaches the equilibrium value [27,[35][36][37].…”