摘要
在凝固速率1-500 μm／s的范围内,Cu-70％Sn包晶合金定向凝固组织由ε相、包晶η相和共晶体组成,ε相为 领先相与最高界面生长温度假设的分析一致.理论计算结果显示,当凝固速率大于22.35 mm／s时,η相可直接从液相中析出, 无需通过包晶反应进行.凝固速率越低,ε向η相固相转变系数越大,造成ε相尺寸在1-5μm／s范围内变化很小,而包晶η 相的体积分数随凝固速率的增加呈现先减后增的变化趋势.在凝固速率小于50#m／s时, Cu-70％Sn包晶合金一次枝晶间距 满足λV0.325=199.5μm1.325·s-0.325;在凝固速率高于50μm／s时,一次枝晶间距满足λV0.528=676 μm1.528·s-0.528.
Directionally solidified microstructure of Cu-70%Sn peritectic alloy consists of primary epsilon, peritectic eta and the eutectic phase (eta+Sn), which is different from the equilibrium microstructure consisting of eta phase and eutectic phase. The theoretical analysis results indicate that eta phase can be directly precipitated from melt, as the growth rate is more than 22.35 mm/s. At the growth rate ranging from 1 to 5 mu m/s, the size of epsilon phase doesn't decrease due to the change of the solid transformation coefficient between epsilon and eta phases, which contributes to the peritectic transformation. With the increase of growth rate, the volume fraction of eta phase firstly decreases and then increases. The primary dendritic arm spacing (A) of Cu-70%Sn alloy and growth rate (V) have a relation of lambda V-0.325=199.5 mu m(1.325).S-0.325 as the growth rate is less than 50 mu m/s. While, at the growth rate from 50 to 500 mu m/s, the value of lambda V-0.528 is equal to 676 mu m(1.528).s(-0.528).
出处
《金属学报》
SCIE
EI
CAS
CSCD
北大核心
2005年第4期411-416,共6页
Acta Metallurgica Sinica
基金
国家自然科学基金项目50395102
50401014航空科学基金项目01G53038西北工业大学英才计划项目资助
关键词
定向凝固
Cu-70%Sn包晶合金
枝晶间距
显微组织
directional solidification
Cu-70%Sn peritectic alloy
primary dendritic arm spacing
microstructure
