Studies On The Heat Transfer And The Main Structure Of Bi-directional Solidification

Bi-directional solidification,as a new study field of solidification technology,is concerned. Compared with uni-directional solidification,bi-directional solidification involves more complicated condition of technology,especially,the bi-directional solidification of superalloy is experimented in high-temperature field which is above 1400C. Owing to poor heat conductivity of Ni-alloy,it is ncessary to study its parameters of heat transfer,which benefit the growth of directional organization. With the further development of solidification technology from uni-directional to bi-directional,the differences in property and organization structure between uni-directional solidfication and bi-directional solidification will be indicated.The author has the honor of taking part in the country's 863 project "Integrated Casting and Uses of Bidirectional Solidification",directed by Porf. Liao Shijie. Led by Teacher Liao,we made great progress in the project:many property,such as,tension,endurance and creeping resistance are statisfactory,and some of them are even superior to the property of original sample of uni-directional solidification. These studies provide a substantial basis for the further study on bi-directional solidification and its practical use.In the chapers that follows,the parameters of heat transfer are computed,the tendence of heat transfer about bi-directional solidification is obtained;texture are studied,the growth direction of crystal can be judged;the main microscopic phase and microstructure of stacking fault are observed,the superiorites represented by bi-directional solidification are explained.