Sn-36%Ni peritectie alloys were directionally solidified at different growth rates under a constant temperature gradient （20 K/mm）, the dependences of microstructural characteristic length scales on the growth rate ...Sn-36%Ni peritectie alloys were directionally solidified at different growth rates under a constant temperature gradient （20 K/mm）, the dependences of microstructural characteristic length scales on the growth rate were investigated. Experimental results are presented, including primary and higher order dendrite arm spacings 21, 22, 23 and dendrite tip radius R of primary NisSn2 phase. Comparisons between the theoretical predictions and the experimental results show that, for the primary dendrites, 21=335.882v-0.21, which is in agreement with the Kurz-Fisher model; for the secondary dendrites, λ2=44.957v-0.277, which is consistent with the Bouchard-Kirkaldy model; for the tertiary dendrites, λ3=40.512v-0.274; for the dendrite tip radius, R=22.7v-0.36. The experimental results also show that the 21/22 changes greatly with increasing growth rate while the 21/23 has no significant change, indicating that tertiary dendrite arms have a more similar growth characteristics to primary dendrites compared with secondary dendrites. The λ1/R ranges from 2 to 2.3 with the increase of growth rate. Key words： Sn-Ni alloy; directional solidification; dendrite arm spacing; dendrite tip radius展开更多
基金Projects （51071062, 51271068, 51274077） supported by the National Natural Science Foundation of China Project （2011 -P03） supported by Open Fund of State Key Laboratory of Mold and Die Technology of Huazhong University of Science and Technology, China+1 种基金 Project （HIT. NSRIF. 2013002） supported by the Fundamental Research Funds for the Central Universities, China Project （2011CB610406） supported by the National Basic Research Program of China
文摘Sn-36%Ni peritectie alloys were directionally solidified at different growth rates under a constant temperature gradient （20 K/mm）, the dependences of microstructural characteristic length scales on the growth rate were investigated. Experimental results are presented, including primary and higher order dendrite arm spacings 21, 22, 23 and dendrite tip radius R of primary NisSn2 phase. Comparisons between the theoretical predictions and the experimental results show that, for the primary dendrites, 21=335.882v-0.21, which is in agreement with the Kurz-Fisher model; for the secondary dendrites, λ2=44.957v-0.277, which is consistent with the Bouchard-Kirkaldy model; for the tertiary dendrites, λ3=40.512v-0.274; for the dendrite tip radius, R=22.7v-0.36. The experimental results also show that the 21/22 changes greatly with increasing growth rate while the 21/23 has no significant change, indicating that tertiary dendrite arms have a more similar growth characteristics to primary dendrites compared with secondary dendrites. The λ1/R ranges from 2 to 2.3 with the increase of growth rate. Key words： Sn-Ni alloy; directional solidification; dendrite arm spacing; dendrite tip radius
