Measurements of cell and primary dendrite arm spacings in directionally solidified aluminium alloys

Design and Product Optimization for Cast Light Metals

“…4.5.5 is the minimum stable spacing, predicted by the model and the dashed line is the maximum spacing taken as three times the minimum spacing (Wan, Han, and Hunt, 1997). The open circles are the experimentally measured average spacing taken from the data in the literature (McCartney and Hunt, 1981). As expected, the measured average spacing falls into a band defined by the calculated minimum stable spacing and the maximum stable spacing for silicon varying from 0.3 to 7 at.…”

Untitled

“…Actually, it was pointed out that the thermal conductivity of TiN and TiC exhibit an increase with temperature [11,12], in contrast to pure metals where the thermal conductivity is almost independent of temperature. It was proposed [13] that the thermal conductivity is dominated by the electrons as heat carriers and not by the phonons. The former contribution increases as a function of temperature due to the numerous defects present in TiN and TiC, whereas the phonon scattering by defects reduces the lattice conductivity.…”

Characterization of the Al-3wt.%Si alloy in unsteady-state horizontal directional solidification

“…A number of directional solidification studies have been reported in the last decades to point out the effect of microstructure upon the mechanical properties, and different approaches and equations have been used with the purpose of modeling both theoretically and experimentally the primary and secondary dendrite arm spacings as a function of alloy solute concentration (C O ), transient metal-mold heat transfer coefficient (h i ), tip growth rate (V L ), temperature gradient (G L ) ahead of the macroscopic solidification front, tip cooling rate (T R ) in the melt, type of mold and melt superheat [14][15][16][17][18][19][20][21][22][23][24][25] . Most studies have shown that for steady or unsteady growth conditions, the primary dendrite arm spacings decrease as the solidification rate or temperature gradient increases; however, there is no agreement in the literature regarding the effect of the alloy solute content on primary spacings.…”