Effects of Growth Rates and Compositions on Dendrite Arm Spacings in Directionally Solidified Al-Zn Alloys

Effect of Growth Velocity and Zn Content on Microhardness in Directionally Solidified Al-Zn Alloys

“…The growth morphologies of the directional solidified Al-(7, 10, 20) wt.% Zn alloy for the lowest and the highest growth velocities (a1-a4) Al-7 wt.% Zn, (b1-b4) Al-10 wt.% Zn, (c1-c4) Al-20 wt.% Zn.constant temperature gradient (10.3 K/mm), fine dendrites formed, as shown inFig. 5 (b 3 ,b 4and c 3 ,c 4 )29 .…”

“…Dendritic morphologies are frequently observed during the solidification of alloys in which several directional solidification studies have been carried out to predict the growth conditions for development of the instability at the solid-liquid interface and characterize the microstructural features [24][25][26][27][28][29] . To minimize the convection in the alloys during solidification, it is necessary not only to have a hydrodynamic density gradient and G, but also a horizontal density gradient, and G could be close to zero in the Bridgman method.…”

“…When alloys are directionally solidified in Bridgman-type equipment, the solidification results in two or more phases aligned in growth direction. In directional solidification experiments, solidification processing variables such as the solidification front velocity, V, the temperature gradient, G, and composition of the material, C o , can be independently controlled in order to study the dependence of the microstructure [26][27][28][29] . One of the most important quantities used to describe the solidified dendritic microstructure in directional solidification is the cellular and dendritic spacing.…”

A Simplified Scaling Law of Cell-Dendrite Transition in Directional Solidification

“…During directional solidification, the onset of sidebranches means the occurrence of cell-dendrite transition (CDT). Over past few years, the identification of CDT has been widely performed experimentally [7][8][9][10][11], which showed that cell and dendrite coexist over a large range of control parameters. Given pulling velocity and thermal gradient, small primary spacing corresponds to cellular morphology in CDT region, while large primary spacing corresponds to dendrite.…”

“…Although sidebranching dynamics has received considerable attentions in free dendritic growth [1,[4][5][6], only some basic understanding about the sidebranching dynamics has been obtained in directional solidification [7,[10][11][12][13][14][15]. Gerogelin et al [7] presented a model to describe the sidebranching dynamics, in which the noise amplitude at the cellular tip was controlled by the feedback of sidebranches.…”