EFFECT OF Nb AND Ti CONTENTS ON MICRO-SEGREGATION OF J-90 ALLOY
WANG Anchuan; LI Yiyi; LI Dongfa; YANG Ke; FAN Cungan; SHI Changxu(Institute of Metal Research; Chinese Academy of Sciences; Shenyang 110015)
Cite this article:
WANG Anchuan; LI Yiyi; LI Dongfa; YANG Ke; FAN Cungan; SHI Changxu(Institute of Metal Research; Chinese Academy of Sciences; Shenyang 110015). EFFECT OF Nb AND Ti CONTENTS ON MICRO-SEGREGATION OF J-90 ALLOY. Acta Metall Sin, 1995, 31(5): 216-222.
Abstract EMPA has been performed to investigate the distribution of Nb and Ti in the solidification structure of J-90 alloys with different contents of Nb and Ti. With increasing of Nb content in the alloy, Nb tends to be seriously segregated, while distribution of Ti becomes more and more homogeneous, but when the content of Ti in the alloy being increased, segregations of Nb and Ti are all lessened. By increasing contents of Nb and Ti in the alloy, partition coefficients of Nb and Ti at the beginning of solidification are all increased. It was found by comparison that difference between the highest and the lowest content of an element after solidification is a more proper parameter for description of elemental segregation which is dependent on the content of elements and the elemental partition coefficient. The fact that k_(Nb) and k_(Ti) increased with increasing of Nb and Ti contents in the alloys indicated that when contents of trace elements (such as P etc.) were lowered, on the solute-rich layer during solidification there would be less these trace elements while contents of easy-segregated elements, such as Nb and Ti, could increased. As a consequence, k_(Nb) and k_(Ti) would increase and micro-segregation of Nb and Ti would decrease.
