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在5 K.mm-1温度梯度下,选用1,5,10 mm.min-1三种拉速率对成分为96.0%Al,1.0%Ni,3.0%Y的三元共晶合金进行定向凝固实验,研究下拉速率对合金组织演化的影响规律。通过X射线衍射和光学显微镜分析表明合金由α-Al相、Al3Y相、Al23Ni6Y4相三相组成。当下拉速率为1 mm.min-1时,合金组织呈现三相共晶结构,纵截面有定向凝固趋势;下拉速率为5和10 mm.min-1时,合金组织演变成两种二相共晶:一种是Al3Y相与α-Al相形成菊花状的不规则二相共晶组织,另一种是Al23Ni6Y4相与α-Al相形成层片状的规则二相共晶组织,纵截面上均有明显的定向凝固特征。
Directional solidification experiments were carried out on ternary eutectic alloys with composition of 96.0% Al, 1.0% Ni and 3.0% Y under the temperature gradient of 5 K.mm-1 at the rates of 1, 5 and 10 mm.min-1 , The influence of pull rate on the microstructure evolution was studied. By X-ray diffraction and optical microscopy analysis shows that the alloy from the α-Al phase, Al3Y phase, Al23Ni6Y4 phase three-phase composition. When the pull-down rate was 1 mm.min-1, the alloy structure showed a three-phase eutectic structure with directional solidification in the longitudinal section. When the pull-down rates were 5 and 10 mm.min-1, the alloy structure evolved into two kinds of two-phase Crystal: one is the formation of an irregular two-phase eutectic structure of Al3Y phase and α-Al phase, and the other is a regular two-phase eutectic structure of Al23Ni6Y4 phase and α-Al phase, Have obvious directional solidification characteristics.