GH4033高温疲劳失效行为及基于VIC-3D的拉伸性能研究

Study on High Temperature Fatigue Failure Behavior and Tensile Performance of GH4033 Superalloy Based on VIC-3D

采用VIC-3D非接触式测量技术分析了GH4033高温合金的拉伸性能,并基于此研究了其工程应力-工程应变曲线和真应力-真应变曲线。通过VIC-3D技术可表征试样截面积以及塑性区的变化趋势,而截面积的变化对材料的力学性能计算有显著影响,特别是在塑性变形阶段。塑性区随时间的增加逐渐扩大,并且试样的伸长率是由塑性区的形变引起的;研究了GH4033高温合金在不同温度和不同载荷作用下的高温疲劳性能,并利用SEM对疲劳断口进行分析以探究失效机理。结果表明:氧化作用随着实验温度的升高不断加剧,氧化产物不仅可以起到楔子作用,促进疲劳裂纹的扩展,而且在试样受压应力时能有效的阻碍裂纹的愈合。随着载荷的增大,二次裂纹数量增多。

The tensile properties of GH4033 superalloy were analyzed by VIC-3D non-contact measurement technology.Based on this, the engineering stress-engineering strain curve and true stress-true strain curve were studied. The variation trend of cross-sectional area and plastic zone could be represented directly by VIC-3D technology, and the change of the cross-sectional area of the material has a significant effect on the calculation of the mechanical properties of the material,especially, in the plastic deformation stage. The plastic zone increases with the time increasing, and the elongation of the specimen was caused by the deformation of plastic zone. The high temperature fatigue performance of GH4033 superalloy at different temperatures and loads were studied and the fatigue fractures were analyzed by SEM to explore the failure mechanism. The results show that with the temperature increasing, the load becomes larger, the fatigue life of GH4033 superalloy becomes shorter. The oxidation effect increases with temperature increasing, the presence of the oxide accelerates the fatigue crack growth and prevents the crack healing under the compressive stress. With the load increasing, the number of secondary cracks become bigger.