摘要
通过对 1 8Cr2 Ni4WA钢在不同应力比和不同载荷下的疲劳裂纹扩展速率试验 ,拟合得Paris关系式 ,然后对试验断口进行疲劳条带宽度 S(微观裂纹扩展速率 )测量 ,将疲劳条带宽度值代入拟合的 Paris关系式中 ,反推计算断口试样的疲劳应力变幅。结果表明 ,疲劳条带宽度只在疲劳裂纹扩展的一定阶段与宏观裂纹扩展速率相等 ,选择该阶段的数据点进行疲劳应力变幅反推计算 ,相对误差在 1 0 %以下 ;数据点是否位于宏、微观裂纹扩展速率相等的阶段 ,可由 S～ yπa双对数座标 S形曲线判定 ,并发现由于裂纹扩展速率的误差传递系数小于 0 .5。
Fatigue crack propagation rate experiment on 18Cr2Ni4WA steel at different stress ratios and under different loads has been conducted,paris equation has been obtained by data fitting, fatigue striation width has been obtained through fractographic observation under TEM. Then, fatigue stress amplitude have been retroestimated by substituting striation widths into the obtained Paris equation. The result shows that the fatigue striation width only equals the macro propagation rate over a certain stage, which can be judged by the way of plotting the striation width and the parameter yπa double logarithmic coordinates S shaped curve. The relative errors of the retroestimated fatigue stress amplitude are less than 10% by the data spots at this stage, The result also reveals that relative errors of the retroestimated fatigue stress amplitude are not sensitive to that of the fatigue crack propagation rate.[KH3/4D]
出处
《航空材料学报》
EI
CAS
CSCD
2000年第4期34-40,共7页
Journal of Aeronautical Materials
