Inconel783高温合金螺栓的组织与织构

研究了Inconel783高温合金螺栓的组织结构与织构特点,重点关注β相的分布与析出特征,并研究了高温应力松弛前后组织与织构的变化情况。结果表明,螺栓试样γ相晶粒分布较为均匀,同时存在弥散分布的γ′相析出。大颗粒的β相沿螺栓轴向成串分布,其分布特征与γ相晶粒取向及尺寸无关,主要由冶炼方式与热加工过程决定;较小的β相在γ相晶界与晶内、连续或孤立析出。织构方面,γ相与β相均未表现出强织构,与热加工过程中变化的多向应力状态有关。以螺栓轴向(x方向)为试样参考方向,γ相存在一定的<111>//x与<100>//x择优,其中前者强度稍高。高温应力松弛试验后,γ相组织、β相分布与各相织构均较为稳定。对该合金中发挥重要作用的小尺寸β相分析发现,其析出行为受到γ相基体取向与晶界特征影响,其中<111>取向晶粒内析出较多,孪晶界上β相析出不占优势。因此,通过控制热加工与固溶处理过程中γ晶粒尺寸与取向择优,有望调控其析出特征。

Microstructure and texture of Inconel783 superalloy bolt

Microstructure and texture of Inconel783 superalloy bolts were studied, and β phase precipitation characteristic was paid special attention, meanwhile the microstructure and texture changes after stress relaxation experiment at high temperature were investigated. The results show that the grain size of γ phase is homogeneous, and γ′ precipitates distribute dispersely. Large β-phase particles are shown to align regularly, with the longitudinal axis parallel to the axis direction of bolt. The distribution of β-phase particles does not depend on the γ phase grain orientations and sizes, while it is mainly determined by smelting and hot deformation processes; the small β-phase particles precipitate at γ phase grain boundaries and inside grains, continuously or separately. Regarding texture, neither the β nor γ phase texture is strong, showing the effect of changing multi-directional stress during hot deformation. Using the axis direction of bolt as the sample reference direction x, <111>//x texture with higher intensity and <100>//x texture are observed in γ phase. The γ phase microstructure, β phase distribution and the textures of both phases are stable during stress relaxation at high temperature. By analyzing the distribution of essential small β-phase particles in Inconel783 superalloy, it is found that the precipitation behavior is influenced by the orientation of γ phase matrix and grain boundary characteristic. More small-sized β-phase precipitation occurs in <111>//x oriented γ grains, while the precipitation quantity does not show advantage at twin boundaries. It can be deduced that the precipitation of small-sized β-phase particles could be modified by controlling the grain size and texture evolution of γ phase during hot deformation and solution treatment processes.