Phase equilibria in Ni-Ti-Ta ternary system

Ni-Ti-Ta三元体系的相平衡关系

Phase diagrams of two isothermal sections of the Ni-Ti-Ta ternary system at 1000 and 1200℃in a full composition range were determined by X-ray diffraction and electron probe microanalysis.The experimental results indicated a ternary compoundτphase with low solid solubility and composition ranges of(16.3-22.4)at.%Ta,(15.9-24.1)at.%Ti and(58.5-60.0)at.%Ni at 1000℃.The two terminal solid solutions(bcc-(Ta)andβ-Ti)formed a continuous solid solution at 1000 and 1200℃.A certain amount of Ti can dissolve into Ni-Ta intermetallic compounds near the Ni-Ta side,with the highest value of 21.9 at.%observed in the Ni;Ta compound at 1000℃.

采用X射线衍射和电子探针显微分析方法,获得Ni-Ti-Ta三元体系在1000和1200℃的全成分范围内等温截面相图。实验结果显示,Ni-Ti-Ta三元体系的1000和1200℃等温截面相图中均存在一个固溶度较小的三元化合物τ相,且通过相平衡可知,该相在1000℃的成分为(16.3~22.4)%Ta,(15.9~24.1)%Ti和(58.5~60.0)%Ni(摩尔分数)。此外,在这两个等温截面相图中,bcc-(Ta)和β-Ti均形成连续的固溶体。Ti在NiTa二元化合物中均有一定的固溶度,其中,1000℃时Ti在Ni;Ta中的固溶度达21.9%(摩尔分数)。