镍基高温合金中非金属夹杂物成分和特征控制

通过扫描电镜和能谱仪等设备,检测分析镍基高温合金中铝和钛含量对夹杂物的成分、形貌、尺寸、数量、夹杂物间的界面间距和面分布等参数的影响。通过经典热力学计算方法、FactSage软件,计算和分析冶炼过程中夹杂物的生成和演变。结果表明,镍基高温合金中夹杂物主要成分为Al₂O₃、Ti_xO_y、TiN,经典热力学计算和FactSage软件计算结果与夹杂物成分检测结果基本吻合。冶炼后期,高铝钛镍基合金、低铝钛镍基合金中夹杂物尺寸相差不多,但是高铝钛镍基合金中夹杂物数量明显较少,夹杂物界面间距较大,夹杂分布更加均匀。通过经典形核理论计算得出,高铝钛镍基合金中夹杂物形核半径是低铝钛镍基合金的3倍,在结合氧相同的情况下,增加合金中铝钛添加量,有利于减少夹杂物的形核数量,从而增加夹杂物的界面间距,减少夹杂物间的碰撞,减弱夹杂物间吸引,减少夹杂物间的聚集。

Control on composition and characteristics of non-metallic inclusions in nickel-base superalloy

In order to explore the influence of aluminum and titanium contents on the composition, morphology, size, number, interfacial spacing and area density of inclusions in nickel-based superalloy, high-temperature experiments were carried out, and devices such as scanning electron microscope(SEM) with energy spectrometer(EDS) were used. The formation and evolution of inclusions were calculated and analyzed by using the classical thermodynamic calculation method and FactSage software. The results showed that the main components of the inclusions in the nickel-based superalloy were Al₂O₃, Ti_xO_y and TiN. The classical thermodynamic calculated results and FactSage software calculated results were consistent with the observed composition of inclusions. The size of inclusions was similar in high Al-Ti nickel-based superalloy and low Al-Ti nickel-based superalloy at the later smelting stage. However, the number of inclusions was significantly less, the interfacial spacing of inclusions was larger, and the distribution of inclusions was more homogeneous in the high Al-Ti nickel-based superalloys. The classical nucleation theory calculation indicated that the nucleation radius of inclusions in high Al-Ti alloy was three times larger than that in low Al-Ti alloy. In the case of the same combined oxygen, increasing the addition amount of Al-Ti was beneficial to decrease the number of nucleation, thereby increasing the interfacial spacing of inclusions, reducing the collision of inclusions, weakening the attraction between inclusions, and decreasing the aggregation between inclusions.