Nb-Ni-Ti系低Ti侧三元化合物及其相平衡

采用合金平衡组织结构分析法，利用扫描电镜组织观察和能谱成分分析、电子探针定量成分分析以及X射线衍射结构分析，并结合热分析，对Nb-Ni-Ti系低Ti侧化合物XB及其相关相平衡进行了研究.结果表明，在Nb-Ni-Ti三元系1000℃和1100℃等温截面相图中都存在着三相区XB+(Nb)+TiNi，化合物XB可与Nb基固溶体(Nb)和TiNi相保持固态相平衡直到约1133℃.Nb-Ni-Ti三元系在1133℃发生三相共晶转变LTiNi+XB;由于液相L的形成，XB相不再与TiNi相和Nb基固溶体平衡.1150℃时Nb-Ni-Ti三元系等温截面相图中存在着XB+(Nb)+L三相区，XB相与Nb基固溶体和液相平衡共存.

Ternary Compound and Relative Phase Equilibria in the Low Ti Side of Nb Ni Ti System

The phase transformation and phase equilibria related with the ternary compound XB in the low Ti side of Nb Ni Ti system were systemically investigated through the equilibrated alloy method by using the scanning electron microscopy(SEM)assisted with energy dispersive spectroscopy of X ray(EDS)， electron probe microanalysis(EPMA)， X ray diffraction(XRD)and differential scanning calorimetry(DSC). It has been shown that the three phase field XB+(Nb)+TiNi exists at both 1000℃ and 1100℃ isothermal sections of the phase diagram in the Nb Ni Ti system. The compound XB could be in solid state equilibrium with the Nb based solid solution(Nb)and the TiNi phase till about 1133℃. There exists the eutectic phase transformation LTiNi+XB at 1133℃ in the Nb Ni Ti system. As the liquid forms， the compound XB could not be in equilibrium with the Nb based solid solution and the TiNi phase. The three phase field XB+(Nb)+L exists at 1150℃ isothermal sections of the phase diagram in the Nb Ni Ti system， XB keeps phase equilibrium with the liquid and the Nb based solid solution.