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colonies (Fig. 1(a)). As shown in Fig. 1(b), the interdendritic dark contrast area exhibits the microsegregation obviously, and the EDS results show that the area is rich in Al and poor in Nb. This shows... microsegregation in Ti-45Al-8.5Nb-(W,B,Y) alloy after 500 and 1000 thermal cycles tests. Compared with the original microstructures in Fig. 1(b), the Al microsegregation can be reduced notably due......
Introduction The solute redistribution during solidification leads to microsegregation and the formation of coarse intermetallic particles, which can significantly influence the properties and productivity... F Y, KRAFT T, ZUO Y, MOON C H, CHANG Y A. Microstructure and microsegregation in Al-rich Al-Cu-Mg alloys [J]. Acta Materialia, 1999, 47(2): 489-500. [6] Joseph H M, Hyman R. Influence......
to the location of high microsegregation. Finally a fine cellular structure is produced. Compared with Fig.1, present one shows a finer cellular structure, that is, more survived cells, weaker microsegregation and thinner solute diffusion layer at the interface, which implicates a transition from cellular dendrites to fine cellular structures due to increase of growth velocity during directional......
and W has been reported previously[5, 8]. Thus, the white-coloured network can be attributed to the remainings of the primary β phase βr[19]. The microsegregation of Nb to dendrite cores occurred... to identify the microsegregation in Fig.3(a). The result (Figs.3(b-e)) reveals that the interdendritic black area exhibits solidification microsegregation that is rich in Al and poor in Nb. It Fig.2 X......
investigations reveal homogeneous distribution of coherent Al3Zr precipitates in dendrite centres, but inhomogeneous distribution at dendrite edges and in interdendritic regions (Fig. 1). Microsegregation of Zr in the Al solid solution during solidification was studied previously [12]. Compositional analysis of a dendrite by line scan on an electron microprobe confirmed the Zr microsegregation......
are relatively high, i.e. chemical microsegregation. Theoretically, a feedstock material containing microsegregation is prerequisite for semi-solid processing, which enhances SSM processability by reducing... particles, which is attributed to the difference of local solute content as a result of microsegregation and inhomogeneous diffusion. In addition, the number and size of these liquid droplets rely......
Fitted distribution coefficients for constituent elements in experimental alloys 4 Discussion 4.1 Effect of carbon and boron on microsegregation It has been obtained that the segregation behavior... the permeability of the dendritic network and retards the local fluid flow. The effect of the thermal solutal convection on the microsegregation depends on the solid fraction. The onset of fluid flow due......
description of the Al-Fe-Mg-Mn-Si system and investigation of microstructure and microsegregation during directional solidification of an Al-Fe-Mg-Mn-Si alloy [J]. Zeitschrift fuer Metallkunde, 2005......
but also microsegregation during the ingot solidification. In other words, the microstructure of the chips was composition inhomogeneous. Fig.5 Microstructures of solid phase: (a) Dendrite... by microsegregation, not by liquid entrapped. In summary, there are two types of solid phase in thixomolded microstructure, that is, the unmelted chips and the molten solid phase. The former is main part......
properties of Al-Cu-Li alloys are sensitive to the microstructure of as-cast alloys, heat treatment, and subsequent processing. During casting, the microsegregation of main elements cannot be avoided, along... alloys [14-16]. By homogenization treatment, these residual phases can be redissolved into the matrix; microsegregation can also be reduced or even completely eliminated. Thus, homogenization......