The microstructure and phase relationships in rapidly solidified type 304 stainless steel powders

High strain rate deformation microstructures of stainless steel 316L by cold spraying and explosive powder compaction

“…In consequence, the reachable undercoolings with respect to the melting point are sufficient to quench in the metastable ferrite present in the fine powders, favoured by its lower surface energy in the surrounding liquid [24]. In contrast, the solidification of bigger droplets is not triggered by such high undercoolings, and thus should result in the nucleation of the equilibrium fcc structure [24,25]. The powder particles are exposed to strong shock pressures during cold spraying or explosive compaction, leading to the transformation of metastable bcc structures to austenite having a higher density.…”

Formation of two-phase coupled microstructure in AISI 304 stainless steel during directional solidification

“…[1][2][3][4][5][6] However, the solidification behavior of austenitic stainless steels is complicated because of the occurrence of a variety of ferrite morphologies during the solidification and subsequent solid-state transformation. Interpretation of the formation mechanism of the different ferrite morphologies is difficult due to the nonequilibrium solidification conditions and the subsequent solid-state transformation on cooling.…”

Rapid solidification of martensitic stainless steel atomized droplets

“…As a result of the increase in the chromium content in the liquid, the bcc phase was stabilized, while the depletion in chromium within the dendrite stabitemperature increased, for powder particle sizes of 30 to 45 lized the fcc phase. This type of solidification behavior was m. Figure 8 shows the fraction of fcc as a function of also reported by Wright et al [6] The martensite which is temperature for different particle sizes. The volume fraction found within the dendrite arms (Figure 3) is the result of was calculated using the ratio of the integrated intensities transformation of the fcc phase into martensite.…”

“…Small droplets have, therefore, the lowest probability of nucleation, while larger particles have the highest probability of nucleation. [2,6,7,[18][19][20] Consequently, in the small particle sizes, the liquid is undercooled to a low temperature before the initia- [15] (open triangle) cooling rate calculated bcc for small particle sizes was earlier shown to be nucleation according to Ṫ ϭ 6h(T melt Ϫ T gas )/C L P d; and (filled line) as calculated by the numerical model. [15] controlled.…”

“…The base material was gas atomized 304, 303, 316, and 308 austenitic stainless steel powders using argon gas, with an atomizing gas pressure of 7 MPa have been reported. [5][6][7][8] The results revealed that the fraction and melt temperature of about 100 K above the liquidus of the metastable bcc phase increases with decreasing powtemperature. More details of the atomizer used in the present der particle size.…”