Silicon Laves phases

Fig. 1. Specific yield strength (0.2 % proof stress in compression per unit weight density at 10 4s 1 strain rate in compression) as a function of temperature for the D022 phase Al3Nb [112, 113], the Heusler-type phase Co2TiAl [67], the Laves phasesTiCr15Si05 andTaFcAl [67,114], the two-phase alloy NbNiAl-NiAl with 15 vol.% NiAl in the Laves phase NbNiAl [67,114], and the hexagonal D8g phase Ti5Si3 [100] in comparison to the superalloy MA 6000 (in tension) [115] and the hot-pressed silicon nitride HPSN (upper limit of flexural strength) [116],...

Under a much higher pressure of 15 GPa, CaAl2Si2 decomposed to Ca(Al,Si)2 with the Laves phase structure [60]. The Laves phase compounds with transition metals are well known for superconductors with the C15 structure, which also belongs to space group Fd3m isotypic with the type II silicon clathrate compounds. Solid solutions Ca(Ali cSi c)2 (0.35 < x < 0.75) can be directly prepared under HPHT conditions of 1,000 °C and 13 GPa. The stoichiometric Laves phase compound CaAlSi shows superconductivity at = 2.6 K. This is the hrst Laves phase compound composed of only commonly found elements. The compound can... 

Control of iron and silicon minimize Laves phase levels in wrought Inconel718. 

For example, the formation of nonequilibrium y, y, and G phase have aU been observed in 316 stainless steels [32]. Both RIS and RIP are observed in the 250—300°C range in 300 series austenitic stainless steels. Due to enrichment of nickel and silicon at defect sinks, the G-phase sUicides are present after modest irradiation fluences [48]. In addition, many other types of phases have been observed in irradiated stainless steels, including carbides, Laves, and gamma [32]. The extent of precipitation and type of precipitates are extremely sensitive to the exact temperature, dose, and dose rate, but are also dependent on the specific damage microstructure. 

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