Ti14Cu合金的定向凝固组织及相研究

Study on Microstructure and Phase of Directional Solidification of Ti14Cu Alloy

研究了100、500、1000μm/s三种抽拉速率下Ti14Cu合金的定向凝固组织演变,通过光学显微镜和扫描电镜观察微观形貌,通过X射线衍射仪测定定向凝固组织中的相。结果表明,随着抽拉速率的提高,柱状晶组织变细且数量增多,枝晶间距减小而枝晶间隙的第二相析出物量增加。当合金成分及温度梯度一定时,二次枝晶间距与抽拉速率成反比。二次枝晶间距的Furer-Wunderlin模拟结果与试验测定的数据相吻合。

The microstructural evolution of directional solidification of Ti14 Cu alloy under the withdrawal rates of 100,500 and 1000 μm/s was studied. The microstructure was observed by using optical microscope and scanning electron microscopy, and the phases in the directional solidified structure were determined by X-ray diffractometer. The results show that with the increase of withdrawal rate, the columnar crystal structure become thinner and the amount increases, and the dendrite spacing decreases,while the quatity of the second phase precipitates in the dendrite gap increases. When the composition and temperature gradient of the alloy are fixed, the secondary dendrite spacing is inversely proportional to the withdrawal rate. The Furer-Wunderlin simulation results of the secondary dendrite spacing are in good agreement with the experimental data.