Strength 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],...

Figure 31 shows yield strength data of two-phase NiAl-NbNiAl alloys as a function of temperature for increasing volume fractions of the strengthening Laves phase. It is noted that the Laves phase precipitates on the grain boundaries and forms a... 

The difference in volume fraction of MC carbides and the nature of the residual phases are reflected in the mechanical and fracture test data. Yield strengths at all temperatures were nearly identical for both alloys in the standard STD A condition. This indicates that the intrinsic alloy strength, which is derived from precipitations of y and y" phases, was not influenced by carbides and other phases. Ductility, fracture toughness, and the FCGR were apparently strongly influenced by carbides and particularly by the Laves phases, which tended to precipitate in the grain boundaries. 

Rhodium. The 100% abundant isotope Rh has spin i, so that its NMR is not complicated by quadrupolar effects. However, its magnetic moment is small (table 18.2), and rather high magnetic field strengths are required for effective measurements. Its NMR has been studied in the cubic Laves phase, LaRh2, by Seitchik et al. (1965). 

A traditional strength, and still a major application, of INS is the study of hydrogen-in-metal systems. In these systems hydrogen occupies a weU-defined lattice site, but is often free to move between sites. This proton mobility has led to numerous applications in battery technology, particularly for LaNisHx and the AB2 Laves phase compounds. The simplest model is to consider that the jumps are all of the same length (1), that jumps in any direction are equally probable, and that the jump time is negligibly small compared to the residence time (r). With these assumptions Equation [6] becomes ... 

The intrinsic strengths of Inconel 718 and Udimet 718 are not influenced by the precipitation of carbides and other (Laves, silicide) phases. 

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