45钢在应变循环与棘轮变形下的随动硬化演化实验研究

AN EXPERIMENTAL STUDY ON THE EVOLUTION OF KINEMATIC HARDENING FOR THE STRAIN CYCLIC AND RATCHETING DEFORMATIONS OF 45 CARBON STEEL

对调质处理的45碳钢进行了不同应变幅值的对称应变和具有平均应变控制下的屈服面半径和背应力演化分析,及具有不同平均应力的低应力、较高应力幅值控制下的屈服面半径和背应力演化分析.研究表明:屈服面半径在给定应变幅值下随循环周次的增加而变小,且随循环塑性应变幅值增大而减小,在单调加载时增大;循环背应力幅值随单调应变而减小,随循环塑性应变幅值增大而增大.

The cyclic tests for the quenched and tempered 45 carbon steel were conducted to analyze the evolutions of the yield surface radius and the back stress for different strain amplitudes with or without mean strains under strain controlled cycling and under cyclic stress for low or relatively high stress amplitudes with different mean stresses. The experimental study shows that the yield surface radius descreases with increasing the cyclic number under the specific strain amplitude and decreases with the increase of the cyclic plastic strain amplitude but increases at monotonic loading; the cyclic back stress amplitude decreases with the monotonic strain while it increases with the cyclic plastic strain amplitude.