Study On The Micro Deformation Mechanism And Multi-scale Constitutive Model For IC10 Alloy

Ni₃Al-based alloys are widely used as hot end components of aeroengines due to their superior mechanical properties such as high temperature yield stress,creep and fatigue behaviors.The micro deformation mechanism of materials determines its macroscopic mechanical behaviors.The deformation mechanism of crystal materials mainly depends on the existence forms and movement modes of micro defects.Dislocation is one of the most important defects in Ni₃-Al based alloys and it has been widely used in the analysis of macro and micro deformation mechanism and the study of various constitutive models in recent years.The researchs on micro deformation mechanism of materials promote the development of multi-scale models.The mechanical behavior and typical characteristic parameters of micro deformation process can be transferred to macro mechanical properties through multi-scale models.In this paper,macro and micro experiments,deformation mechanism analysis,dislocation model researcheson single scale and the establishment of multi-scale model on the typical Ni₃Al-based alloy,IC10 alloy,have been carried out systematically.The main research work and conclusions are summarized as follows:（1）The testson macro mechanical properties and the study on micro deformation mechanism of IC10 alloy were systematically carried out.The macro mechanical properties of IC10 alloy（single crystal and columnar crystal）under different temperatures（298K,673K,973K,1073K and 1173K）and different loading directions（loading angles of 0°,30°,45°,60°and 90°）were summarized.The macroscopic mechanical properties of IC10 alloy（single crystal and columnar crystal）were studied by means of transmission electron microscope and scanning electron microscope.The mechanism of dislocation movement in different deformation stages at 973K and 1173K was analyzed,and the influence of micro deformation mechanism and geometric characteristic parameters on macroscopic mechanical behavior wasstudied.（2）The stiffness model of columnar crystal considering grain boundary and the unified tension compression asymmetry model suitable along different loading directions have been established.The correctness of the two macroscopic models was verified by combining the reported material data and the experimental data,which provides the acquisition of model parameters and the verification of macro data for the development of multi-scale model.（3）For Ni₃Al-based single crystal material,a micro constitutive model considering the deformation mechanism of different types of dislocations was established.Based on the macro and micro experimental results of IC10 single crystal at 298K and 973K,the model data were fitted and model validation was completed respectively.（4）For Ni₃Al-based columnar crystal material,a micro constitutive model of grain boundary is established based on the developed single crystal micro constitutive model and the interaction between dislocation and material grain boundary after yielding.Based on the experimental data of IC10 single crystal,plate C10 columnar crystal and bar IC10 columnar crystal,the validity and practicability of the model were demonstrated.Based on the model,（a）the dislocation density of various types of dislocations in various slip systems in Ni₃Al-based alloy was analyzed and discussed,which was basically consistent with the experimental results.（b）The law of the interaction force between grain boundary and dislocation changing with deformation and position was stuied.（c）The macroscopic mechanical properties of IC10 single crystal,C10 columnar crystal and IC10 columnar crystal were compared and analyzed.The macroscopic mechanical properties of the three kinds of materials were predicted by the grain boundary microscopic model perfectly.（5）Based on the statistical theory and the developed microscopic constitutive model,a multi-scale analysis model was established.According to different microscopic models and statistical characteristic parameters,the multi-scale model was used to predict the mechanical behaviors of IC10single crystal and the mechanical responses of IC10 columnar crystal.The predicted results were effectiveand corrective when the composition of statistical characteristic parameters was enough.