高温下多主元合金的动态变形行为与本构建模OA北大核心CSTPCD

Compared to traditional alloys,the new multi-component alloy exhibits an excellent "cocktail effect". This effect allows for the collaborative control of structure and performance,making it highly suitable for application in the demanding service environment of the aviation industry. Experimental conditions simulating high temperature and high strain rate coupling environments encountered by aero engines are employed to expedite the adoption of multi-principal component alloys in the aviation industry. Using the CoCrFeNiMn multi-principal element alloy as the research object,dynamic impact tests were conducted at different temperatures (298,673,873,1073,1273 K) by using a split Hopkinson pressure bar with an impact velocity of 20 m/s. Dynamic stress-strain curves at five temperatures were obtained,and the results indicate that the stress-strain curve at 1273 K has higher strain-hardening ability compared to 873 K and 1073 K. When the temperature increases to 1273 K,the material's yield strength can still reach 200 MPa,demonstrating good high-temperature performance.The grain size,dislocation density,and microstructure types of the samples before and after deformation were discussed by electron backscatter diffraction tests. The experiment result reveals that an increase in dynamic plastic strain at 1273 K leads to a grain coarsening phenomenon,with higher substructure breeding ability observed at the grain boundary. In addition,the change in adiabatic temperature rise and ambient temperature during dynamic plastic deformation is quantified. It is also highlighted that the current dynamic constitutive relationship is inadequate in predicting the dynamic stress-strain relationship of the CoCrFeNiMn multi-principal component alloy across a wide temperature range. Finally,an exponentially phenomenological dynamic constitutive equation is established by decoupling the temperature effect between the initial yield and the plastic flow stage. This constitutive equation allows for accurate prediction of the yield strength and plastic flow behavior of multi-component alloys under impact loads over a wide temperature range.