On the crystal structure ofZ-phase Cr(V,Nb)N

Kinetics of Z-Phase Precipitation in 9 to 12 pct Cr Steels

“…Thereafter, they were tempered at 1023 K (750°C) for 2 hours, followed by air cooling to obtain a tempered martensite microstructure. The microstructure consists entirely of tempered martensite, no delta ferrite was present, and the average hardness was around 235 HV 10 . After normalizing and tempering, the samples were aged at 873 K, 923 K, or 973 K (600°C, 650°C, or 700°C) for up to 30,000 hours in laboratory furnaces flushed with air.…”

“…[5,8,9] This results in Z-phase having two different crystal structures, which can coexist in a single precipitate particle. [10] The primary Z-phase crystal structure is tetragonal with lattice parameters of a = 0.286 nm and c = 0.739 nm, and it is likely the most thermodynamically stable. The secondary Z-phase crystal structure has a NaCl type lattice resembling that of the MX and is probably metastable.…”

Review of Z phase precipitation in 9–12 wt-Cr steels

“…Measuring the crystal structure of Cr(V,Nb)N and CrVN particles using electron diffraction in [40] has yielded surprising results, as both cubic and tetragonal diffraction patterns could be obtained from the same particles. The cubic crystal structure was measured to have a lattice parameter around 0.404nm, being slightly lower than the VN lattice parameter but corresponding to the lattice in Zphase if it was cubic, see Fig.…”

Thermomechanical controlled processing to achieve very fine grains in the ISO 5832-9 austenitic stainless steel biomaterial

“…In turn, when precipitates coalesce, a degradation of fatigue properties and corrosion resistance of the material is noticed [11][12][13][14][15][16]. The formation of Z-phase is unclear at present and not well established whether it is formed from prior nitride precipitates as proposed by some authors [13,[17][18][19] or directly nucleated as suggested by others [8,20,21]. Indeed, as far as the present authors know, the solubility product of this phase has not been yet reported.…”